Just beating the game isn't that hard, and even getting par death/time is only a matter of not wasting time and not making any mistakes; you don't really need a walkthrough for that (unless you're really stuck on a level… but it's usually enough to just go over available options and you'll find a solution alright). Thus, this guide will be focusing on beating the challenge for death count/timer (purple badges), giving hints on beating the level and/or reaching Jeff sometimes. (Besides, the challenges are the actual fun part of the game).

Also, there are some useful guides with other information:

• general achievements guide
  
• expected challenge times/death counts (as in, “how much you need to get a purple badge”)

The optimal way of completing the game is to start each level first with a thorough investigation of it; try to get Jeff during that time, as you don't care for time nor death count during that run (in most cases you won't cut yourself off from reaching Jeff, but if you realised you did just restart the level). Next, try to beat the level with minimum amount of deaths; this often requires discovering all the ‘shortcuts’ on the level, so you don't waste your knights when you don't have to. After that, go for the shortest time – this usually means doing only the required actions, and making use of every shortcut on the level (or at least most of them); sometimes you have to restart several times to get everything right on the first try – especially if the challenge timer is set to the best time that can be reached. And only after you've beaten the whole game and got all the challenges, should you go for the speedrun challenge.

Here's a few tips that apply to the entire game (mostly for challenge runs):

• The level name can be a hint sometimes
  
• A jump from a ledge (including a spiked knight) without pressing direction goes straight up this gives you best jump height when minimising how many knights you need to spike for a climb
  
  • Falling down from such a jump, you won't catch that ledge again unless you press a direction button (but pressing down is usually a faster way to get down from it)
    
• Background tends to contain hints for certain things like the blatantly obvious hints on what is affected by each switch – you don't actually have to press a button to guess what it does
  
  • or the markers for positioning stuff – like aiming cannons or moving platforms
    
• Timer is not active while the level is being previewed you can take your time to plan out/remember your solution during the speedrun
  
  • But you can start playing the level at any moment during preview this affects timing of repeating events
    
    • like moving lifts or raising lava
      
• For most spiked floors/carts/conveyor belts, you normally only need one knight to deal with it (but you'll have to carefully aim when jumping on him, and take care not to slip)
  
• A knight that was shot is considered to be alive until the first collision
  
  • this means stuff like checkpoints and cups
    
• Spiking a knight at the lower end of a lift makes it easier to catch a ride
  
  • it's even easier if you do it before the lift starts moving
    
• If you're hanging off a knight spiked to a conveyor belt and he's flipping over to the top, jump on his head
  
• Coyote time [en.wikipedia.org]
  
• Bumping a moving object from below can help you get across a gap
  
  • like an ice cube or a zombie
    
    • (in case of a zombie, also jump in the direction it's moving to propel it horizontally as well)
      
• Each undeath machine can support exactly 1 zombie (if you make another, the previous one disintegrates)
  
• Freshly spawned zombie starts moving in the same direction where the original knight was turned
  
• Stand behind a zombie to make it stop walking (and/or turn around after a second)
  
• Standing (or walking) zombie makes for a great trampoline (if you can land on its head, that is)
  
• Bumping a zombie from behind makes it stumble ahead (skipping distance and/or obstacles)
  
  • it stays in place after that for a few seconds
    
• When shooting at a portal, different aiming results in a different trajectory
  
• Certain tricks can be required to beat a level (at least without lots of retries for a lucky shot); they might be helpful in optimising your route in other levels
  
  • like how your jump height is just short of 2 floors, but standing on a corpse makes up for the difference
    
    • pay attention to 2-floor heights in general
      
  • or that it's possible to fry yourself on a magnetic grid and then use magnetism to throw the corpse
    
  • or that it takes a second for an ice cube to melt and it stays a solid block until then (then crumbles releasing its content undamaged)
    

You'll find extra tips for speedrun play (“Beat the Devs” achievement) at the end of this guide.

The following sections describe each level like this:

• First, the level number and title (bonus levels are numbered with an ‘X’)
  
• Then, for the hard(er) levels, you'll find hints to beating the level (in case you need them)
  
• After that, hints on how to find/reach Jeff (unless there's no need for them)
  
• Next, the amount of deaths required to beat the level (usually equal to the challenge death count but sometimes lower), followed by their list (denoting the purpose of each death), along with hints on how to avoid unnecessary deaths (if needed)
  
• Finally, a list of tricks for speedrunning the level (in cases where “make no mistakes and move quickly” isn't enough)

Jeff: left
Required deaths: 2 one per spiked floor

Jeff: down
Required deaths: 1 2nd button

Required deaths: 2 spiked floor, respawn
Tricks:

• Dying on spikes is quicker than falling down

Jeff: top right
Required deaths: 3 2 spiked walls, spiked lift

You can reach the cup if you have something extra to stand on
(this means a corpse)
Jeff: same trick as with the cup
Required deaths: 2 button, footstand

Each fire is toggled twice (on/off and vice versa)
Press last button, get last checkpoint, hit that button again
Jeff: down then left
Required deaths: 3 2 spiked floors, respawn

The cart is usable once the spikes are properly occupied
Jeff: top right
(climb the cart after turning it over)
Required deaths: 3 button, 2x cart (it'll slip off from just one)

Jeff: above the cup
(jump from left conveyor belt)
Required deaths: 2 one per button

Pressing buttons takes effect slowly here
Wait until the gate is at the top point before getting off the button
You can't outrun the gate, so you'll have to take a shortcut
Jeff: top right
(use the second gate to reach him)
Required deaths: 2 left button, respawn

Conveyor belt moves almost as fast as you run… unless you stop it first
Jeff: bottom right
(jump from the rightmost ledge, but at lowest jump height)
(or you can just stop the belt and bump your head into a corpse)
Required deaths: 2 one per conveyor belt
Tricks:

• You don't have to stop the belt if you spike the knight to the right of the checkpoint
  
• You don't have to wait for the first belt to make the full loop
  
  • walk off the ledge
    
  • coyote time is your friend
    

Spiked knights make for great counterweights
Jeff: catapult goes whee!
(pull down the first bridge by jumping onto its right end, then use its momentum to propel your jump)
(that means jumping when it's at the top point)
Required deaths: 1 right button
Lever physics aren't quite perfect here
Jump on the middle of the left shoulder of a bridge then run up the right side while it's rising
Tricks:

• It's faster to use a counterweight for the left bridge
  
• But you can run up the right bridge without one if you land in the right place
  
  • (it's 3/4ths of its left shoulder, counting from the end – right above the wooden support column)
    

The first cannon should be aimed at the crystal
Shoot da swings to make them go fastah
(while they're moving in direction of your shot; and avoid grazing shots, they do nothing)
Jeff: above the last checkpoint
(use the left swing to reach him)
Required deaths: 3 button + one per swing (you can't get on the left one without shooting it first)

Hitting left button once causes tumbler turn to the next button (pressing causes continuous turning until you hop off it)
Blue = gate, green = conveyor belt (+ fires in the corridor)
To hit top button, aim at the crystal
Aim at the ceiling above the end of conveyor belt or right under the gate to land a corpse on the belt
Jeff: top left
(to get the corpse to stop there, hit the button once more when conveyor belt starts moving)
Required deaths: 3 tumbler, top button, left button

Avoid the spinning checkpoints
Hit the button, activate the checkpoint, hit the button again, respawn
Aim at the middle of the wooden ceiling above the cannon – where the chain is connected to it
Jeff: top left
(get left spinning checkpoint, respawn, get the top checkpoint, respawn)
Required deaths: 5 1st fire, spiked wall, 2nd fire, 2nd button, last checkpoint

Bonus levels are hard so I'll provide more hints for these
Effects of buttons, counterclockwise:

1. opens door to the right checkpoint + blocks fire from the left
   
2. lowers right checkpoint to the door
   
3. opens door 2 under the central passage + blocks the first button
   
4. opens door 1 under the central passage + blocks fire from the right + blocks Jeff
   
5. lowers/raises the other 3 moving checkpoints nearby
   
6. opens the gate to the cup
   

Most of the puzzle consists of getting a moving checkpoint, moving that checkpoint, then finding a way to die without touching any other checkpoints so that you spawn at the one you got first.
After hitting the last button, you can run under the closest checkpoint while it lowers, but not the next one.
To reach the last button, you need the second passage to be open (and the fire to be unblocked from the left).
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Jeff: same problem as with the cup
(you can't reach him before the cup gate is open)
(run under the cup to jump off the cliff)
Required deaths: 3 spawn for buttons 3, 4 & 6 respectively

The trick is to get a corpse on the button and run past the turned off flamethrower before the corpse is burned by lava
Required deaths: 2 one per button
Tricks:

• Why wait for lava to rise after level is started if you can start the level when it's already rising?
  
  • start the level when camera stops for the 2nd time
    

Jeff: bottom right of the conveyor belt
Required deaths: 6 spiked floor, lift, button, second button, raft, cup

It's easier to traverse the conveyor belt if you drop a corpse on the first button
Jeff: top right
do not drop a corpse on the first button
(spike a corpse to conveyor belt and jump on top of it – if you miss the first time you'll have more corpses to stand on)
Required deaths: 2 2nd button, 1st button
Tricks:

• Spike a corpse and hop on top of it; do not miss

Drop a corpse from the conveyor belt
The key is when to drop it
(it means dropping when the flamethrower is moving to the left)
Jeff: top right
(if you turn off spikes you can just walk over)
Required deaths: 1 spiked floor

You need to turn off the flame and turn on the spikes
The cannon only needs one target
To get a corpse on the right button, shoot the spikes then turn them off
To get a corpse on the left button, shoot again and then turn on the spikes
Jeff: top left
(shoot again but don't use any spikes)
Required deaths: 4 right button, left button, 2x spiked wall
Tricks:

• You only need to turn on the conveyor belt spikes once
  
  • (do it after the first shot)
    

To turn off the first flame you need to drop a spiked knight on a button
It's blocked when the cart is going right but the knight doesn't have to stay spiked when it's passing the fire
To unblock the cup you need to drop a corpse from the cart using conveyor belt spikes
To unblock the spikes button, drop a corpse from conveyor belt after moving the cart away
Jeff: top right of the first room
(spike a second knight and drop on him… or just walk over)
Required deaths: 3 top button + 2 bottom buttons
Tricks:

• Drop a corpse on the cart then move it away
  
• Spiked cart moves during level preview
  
  • start the level when camera moves towards the cutter wheel
    

Right conveyor belt → cart → top conveyor belt → bottom conveyor belt
Jeff: top right
(use conveyor belt to reach him)
Required deaths: 1 1st button
Tricks:

• Turn over the cart as soon as it reaches the slate, then run to turn on the spikes
  
  • (use coyote time to jump over the gap)
    
• The cart moves during level preview
  
  • (best time to start level is after it begins moving away from you)
    
• Technically you don't even need the cart: if you turn off spikes at the right moment, the corpse will be flinged right at the second conveyor belt
  
  • (don't expect this to work on the first try tho)
    

Stick your knights between the circuits, then remove the corpses with a flamethrower
Jeff: top left
(jump from the cart)
Required deaths: 2 one for each circuit
Tricks:

• Inertia exists here
  
  • (this means you can jump on the cart to hit the button before you actually reached the intended place)
    
  • second position has more acceleration distance
    

By using the first two buttons you can direct the platform to move repeatedly within its range
If it doesn't move where you want it to, turn off one of the buttons until it's positioned on the trajectory
Best trajectory for the level is clockwise circle
Jeff: top right
(direct the platform to move diagonally)
Required deaths: 3 circuit, button, spiked wall
Tricks:

• To get the platform onto the circle trajectory, hit the 2nd button, then 1st when the platform is above the fire
  
• Spike the knight to the right end of the platform
  
• You don't need to wait for the platform to make a full circle, just climb on it and jump over the fire

Buttons under the bridges reset respective circuits
Circuits turn over the moving walls with checkpoints
You need to use the second circuit twice
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Jeff: top left
(use the second pair of contacts then go back to him)
Required deaths: 3 first circuit, 2x second circuit
Tricks:

• You don't actually need to use the 4th button before you've reset the second circuit

Button at the bottom resets the puzzle
Every death counts
If you need to choose between alternatives, think what you're gonna do after
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Jeff: right
(after the cup)
Required deaths: 8 one per circuit + one respawn (fire)

Jeff: top left
(get up without pressing the button)
(place the ice cube next to the button)
Required deaths: 3 ice cube, conveyor belt, ice cube
Tricks:

• You don't have to wait for the conveyor belt to make the whole loop
  
  • Low jump is still reachable and will let you reach the top quicker (but it's easier to miss)
    

Jeff: bottom left of the second room
(jump at him from an ice cube)
Required deaths: 2 one ice cube per frost generator
Tricks:

• Jumping from the moving platform lets you reach the cup before it
  
• The further you push the second cube, the faster it rebounds
  
  • but you don't actually need to push the second cube
    
    • (drop a third cube on it and let it slide off to the left)
      

An ice cube blocks off flames before it melts
Jeff: top right
(stack two ice cubes and push them to the right with the flames turned off)
(respawn if you can't run fast enough)
Required deaths: 2 one ice cube per frost generator
Push the second ice cube up the slope to accelerate it then hop on it and jump over to the cup before it melts

Jeff: bottom right
(delay jumping off the ice cube)
Required deaths: 2 one ice cube per frost generator
You can jump over the flame the moment it lights up if you jump straight up in front of the wooden support in the background then curve to the right as you're about to hit the button

Effects of buttons in the main room, counterclockwise:

1. closes doors to the left and above the first checkpoint
   
2. blocks first button, circuit, and fire under the cup
   
3. rotates frost generator/flamethrower + turns on spiked wall
   

Circuit: moves up the first checkpoint
You need an ice cube to reach the circuit, but you also have to turn away the flamethrower
The second checkpoint forces you to reset the puzzle (so you need to do everything in one go)
Use the spikes to get around the closed door (you'll have to prepare them ahead of time)
3a12
Jeff: left room
(open trapdoor, ready the catapult, supply the ammo, close trapdoor, fire!)
Required deaths: 4 ice cube, spiked wall, circuit, respawn

Just hit the buttons in the order you encounter them, apply companion cube where it's useful
Sometimes you need to get past an ice cube (by sliding it past a hole or respawning)
You can get past a closed gate via respawn
If the cube can't jump over a hole, bump it up from below
Jeff: bottom left
(you can actually reach him without wasting a life from the challenge count!)
Required deaths: 1 ice cube
You can get the cube to slide up high enough by inertia if you push it up the opposite slope first
Death for respawn in the double-gate segment is actually avoidable (though unlike in original release, in Done to Death it's not required for purple badge)
(push the cube up the slope, then let it push you down until it stops at the hatch)
Tricks:

• Make sure you can get the cube across the gap on your first try
  
• If you let the rails close at just the right time, the cube will ricochet from the floor to the left (hard to reproduce)

You can't outrun the conveyor belt, so you'll need additional protection for the corpse
(I meant ice)
Jeff: under the first conveyor belt
Required deaths: 3 2x ice cube, circuit

Jeff: on top of the second ‘sled’
(you'll need to get an ice cube onto rails to reach him)
(ice cubes don't disappear, they're piling up in front of the entrance)
Required deaths: 6 2nd button, one ice cube per frost generator, circuit, cup

Jeff: top left
(jump propelled by magnetism)
Required deaths: 1 button

Magnetism lets you send an ice cube across the gap, but you'll have to wait for the next ride
Jeff: bottom left
(enter magnetic field while falling to counteract its pull)
Required deaths: 2 2x ice cube

Leftmost button turns off the bottom fire, rightmost button turns off the top fire
Jeff: bottom right
(corpses fall through the rails)
(turn off the flame, make an ice cube, send it sliding, then turn on fire again; it should melt on the right slope)
Required deaths: 1 ice cube
You can push the ice cube back once you hit the leftmost button
Tricks:

• You don't have to wait until the ice cube reaches the hole to turn off the magnet
  
• Respawn is faster than walking back
  
• Use magnet to push the ice cube up the right slope, then wait until it slides under the magnet button and turn on magnet again

You need something to stand on to get across the gap
(a corpse)
In case of the last gap it's an ice cube
(you need to stack them before they reach the magnetic field)
And yes, same goes to you as well: you need to get on top of an ice cube before it reaches magnetic field
Jeff: top left of the statue
Required deaths: 6 2 circuits, footstand, 3x ice cube
Carefully stack two ice cubes to get the top one to slide off onto the next floor

First, you need unlock the gate and the floor above magnetic field
(you'll have to turn off the right magnetic field to reach the circuit)
(you'll need to turn it on again to get thrown far down enough to bounce up to the gate)
(2131)
Then, you'll need to drop a corpse into magnetic field and use the turning magnet to direct it into the frost generator
(direct the magnet right under the second flame, and spike the knight on the left end of the platform)
Jeff: above the spiked platform
(climb onto the platform then into the passage above)
Required deaths: 2 circuit, ice cube

The platform to the right is connected with the lift
Magnetic field from the bottom button won't affect it, but a corpse will be pushed up
(drop an ice cube into the bottom passage first)
You can turn off the fire using the top button
(lift an ice cube there)
Jeff: top right
(use another cube to jump from, or rely on momentum)
Required deaths: 3 2x ice cube, bottom button
You don't need to burn the corpse from the first cube while you're getting the second cube to the top

Leftmost circuit: aim slightly above the lower end of the pipe segment under it
Room with lantern: aim directly at the lantern
Move the cart so that the leftmost board on the wall is behind the cannon
(aim at the ceiling above the left wooden support)
Jeff: top right of the room with lantern
(turn off magnetic fields first)
(aim at the 3rd brick from the top)
Required deaths: 7 5 circuits, button, cup

Get a corpse into the magnetic cart and drop it onto the button
(the floor doesn't always kill you but the ceiling does)
Top button in second room turns on spikes (but also flamethrower above the circuit)
Circuit toggles the flamethrowers (but stops the conveyor belt)
You need to get a knight into the circuit before spiking another corpse to the conveyor belt
(use short bursts of magnetism to raise the knight from the circuit without burning him)
Jeff: under the conveyor belt
(same thing as with the button, just avoid stopping at the flamethrower)
Required deaths: 3 button under the top passage, circuit, button under the conveyor belt

Soul trigger is on while the knight who activated it is alive
It unblocks the cup, so you need it activated when you go for it
Use an ice cube to get over the wall
Jeff: top left
(do not activate the soul trigger)
Required deaths: 2 spiked floor, ice cube

Soul trigger toggles all flamethrowers… and also unblocks Jeff
Use a soul trigger, reach a checkpoint, die, respawn
Jeff: top left
(the gate closes slowly)
(open the gate then respawn in front of it)
Required deaths: 3 spiked wall, 2x respawn
You only need to respawn on the cart checkpoint once you reach it

Circuit opens the door to the soul trigger which turns off the bottom flamethrower
You can't make a new corpse after that but you already have one at hand
Jeff: top right
(magnetism propelled jump… twice if you got fried on the first try)
Required deaths: 1 circuit/button
Tricks:

• Hitting the magnetic grid kills you, but using the cutter wheel lets you respawn faster
  
• Preparing a second corpse for the other half of the magnet saves you some time

You need all the soul triggers on at the same time to unblock the cup
(start from the top)
Use the cart to respawn first
Then an ice cube to get into the passage above it
Jeff: top right
(you also need all the soul triggers to be on to reach him)
(this means an extra ice cube to help you climb up again)
Required deaths: 2 respawn, ice cube
Tricks:

• best time to start the level is immediately
  
  • (then run left and jump onto the checkpoint as it's about to enter the fire)
    
  • alternatively wait for the camera to show the checkpoint and start when it's going right
    

You need an ice cube to hit the left button, but a platform is blocking the frost generator, and you'll need to turn off the flamethrower with the soul trigger
Ice cube → soul trigger → right button → ice cube → soul trigger → left button
Jeff: bottom right
(you need an ice cube to reach him)
(hop on the right button and then hop off it to get the ice cube to slide down to the floor)
Required deaths: 2 one ice cube per button

Position the first circuit in the middle, so that the gear in the background is behind left edge of the top crate
To unblock the gate, you need all the circuits in the last room
For the last one, get a corpse on conveyor belt (with the magnet), place the magnet next to the circuit and start the conveyor belt
Jeff: top left in the last room
(you need the 2nd circuit in the room to be on, but the 1st needs to be off)
(use the magnet for that)
Required deaths: 6 5 circuits + button in the second room
Tricks:

• Don't wait for the corpse to hit the first circuit before going down
  
• Send the circuit in the second room ahead after you use it so that it gets back quicker when you need to replace the knight
  
• Prepare the corpse for the last circuit as you're making one for the first circuit in the last room
  
• Inertia
  
• Last circuit: position the magnet → turn on conveyor belt → turn on the magnet → turn off flamethrower

Soul triggers turn on spikes but the first one also turns on the flamethrower, so you need to keep toggling it
Jeff: top left
(catch on to a spiked knight as it starts going up, then hop onto his head)
Required deaths: 5 1 for 2nd button, 4x reset triggers
Reuse the second corpse for the 3rd button
Tricks:

• Get the last corpse onto the conveyor belt before running to the right

Use the cannon to propel the ice cube in the last room
Jeff: top right in the first room
(jump from the ice cube)
Required deaths: 5 one per circuit, 2x last button, impulse (ice cube)
Tricks:

• Push the ice cube to the left first, and jump up from it before it falls off
  
• If you manage to get the ice cube on the last platform with the gate down, it'll be faster to reach

You need a way to turn off the spikes in the last room without touching the soul trigger
(use an ice cube)
(you'll need a second ice cube to get it there)
Jeff: left
(jump off an ice cube)
Required deaths: 3 2x ice cube, flamethrower button

Effects of soul triggers, left to right:

1. turns on the meatgrinder to the left (and the left magnet), and raises the wall above the 3rd one
   
2. lowers the bridge under the magnet + blocks the circuit and the way up from the nearby checkpoint
   
3. turns on the middle magnet
   
4. turns on the flamethrower (blocking the only exit)
   
5. turns on the right magnet (blocking the cup but letting you go up)
   

Circuit opens doors around the 1st soul trigger
Button lowers the bridge above the 5th soul trigger and closes off passage to the cup
Your goal is to respawn at the checkpoint next to the cup
You can only avoid the first checkpoint by lowering the bridge above it
Which means activating the first checkpoint in the passage then hitting the button
But you shouldn't touch the 3rd soul trigger, so you need to raise that wall
And to get to the top from the 1st soul trigger, you need to open the doors first
In general, make sure you have the right checkpoint before respawning
321a12b354
Jeff: left
(you'll need to jump off from a higher ground to reach him)
(get to the gap with the 1st soul trigger turned on then try to jump onto a falling knight somehow)
Required deaths: 4 reset triggers, circuit, respawn, respawn

Jump down the holes then return through passages to the right, in the correct order
The order to open the cup gates is quite simple
Soul triggers in the holes (left to right):

1. turns the right flamethrower (blocking the 4th soul trigger once right flamethrower is on)
   
2. turns the middle flamethrower (blocking the 3rd soul trigger once middle flamethrower is on)
   
3. flips the top flamethrower (unblocking the 1st & 2nd soul trigger if the top flamethrower is on)
   
4. turns the left flamethrower (unblocking the 2nd soul trigger if the left flamethrower is on)
   

Soul triggers in the passages (top to bottom):

1. turns on the left flamethrower (+ blocks the passage)
   
2. turns on the middle and the top flamethrower (+ blocks the passage)
   
3. turns on the right flamethrower (+ blocks the passage)
   

1a4b3c2
Jeff: bottom left
(unblocked by soul triggers in the passages)
(you still need to flip the top flamethrower)
(3abc)
Required deaths: 1 respawn

Yes, ice cubes are there to ride them (apparently some folks keep forgetting this)
To climb the last tower you may want to stop the lift at a very specific place – so that you can reach it and reach the ledge from it; if you fail you can reset the circuit with the magnet
(the position is slightly below the flamethrower – about a knight's head high)
Alternatively (and this is likely much more convenient), fry a knight on the magnetic grid, then fling him at the circuit after touching the soul trigger
Jeff: under the rails below the first frost generator
(turn off the flamethrower, move an ice cube to the right side, then turn it back on and push the ice cube through it)
Required deaths: 9 checkpoint, checkpoint, 2x spiked wall, checkpoint/ice cube, ice cube, circuit, 2x spiked wall
Aim at the ceiling slightly to the left of the 5th checkpoint to both trigger it and freeze that same knight
You don't need to turn off the flamethrower, just jump up from that same ice cube

You should be thinking with portals
(to unblock the portal, use each moving checkpoint in the right passage to activate the respective circuit)
Jeff: top left in the main room
(touch the soul trigger to the left of Jeff and use the portal to reach him)
Required deaths: 8 spiked wall, respawn, 3x(respawn, circuit)
Tricks:

• You don't have to jump vertically to hit a button
  
• You can activate first moving checkpoint as it descends

Speed vector is retained after teleportation
Do not jump into the portal when the checkpoint on the lift is active
Portals work on corpses
You need to unlock the nearby soul trigger before throwing a corpse through the portal
(the button stops the conveyor belt)
Jeff: top right
(activate both circuits and two soul triggers nearby to unblock him)
Required deaths: 3 2 circuits, right spiked floor
The portal removes most need for respawn
Tricks:

• You don't actually need to stop the conveyor belt
  
  • you need to make the last corpse fall left from the cutter wheel to reach the soul trigger in time
    

1st button: aim at the burn mark on the left slope
2nd button: aim at the center of the portal
3rd checkpoint: shoot as it descends near the trajectory, or while it's below
3rd button: to avoid hitting the moving checkpoint, aim at the burn mark on the slope
4th button (before hitting 5th button): activate the moving checkpoint then shoot the portal
4th button (after hitting 5th button): activate the checkpoint next to the cannon then shoot the portal above it
Cup: activate the last checkpoint and shoot the portal above the cannon
Jeff: rightmost end
(after activating the last checkpoint and re-positioning the portal above the cannon, shoot the burn mark on the vertical wall below it)
Required deaths: 7 1st/2nd button, checkpoint, checkpoint, 4th button/footstand, 5th button, 4th button, cup
If you make the first shot at a very specific place you can make the corpse bounce off the 1st button to also hit the 2nd one
(it's exactly under the burn mark)
(this shot is extremely hard to make even if you know where you're supposed to shoot… but it's not actually required for the challenge)
You don't actually need the 3rd button at all
(you can shoot the moving checkpoint above without moving it in the first place)
You also don't need to move the last checkpoint
(you can jump over the wall if you stand on a corpse)
(when making the second shot from the second cannon, aim at the lowest (bottom-right) edge of the portal – the corpse will bounce off and land in front of the right wall)
Tricks:

• You don't need to wait for 3rd checkpoint to make a full circle before respawning

To reach the cup, you need the soul trigger to the right of it to be on, and the one below it to be off
(thus, you have to spawn at the checkpoint in front of the cup, touch the right soul trigger and use the portal)
To turn off the flame you need to hit the button above
(but to leave that place you need two flames to the right to be turned off)
Spike a knight to the wall first
Do not activate the top right soul trigger
Jeff: top right
(after getting past two flames, jump over the gap instead of falling into it)
Required deaths: 2 spiked wall, respawn/reset triggers

To make it across the gap, jump into the portal with acceleration from the magnetic field
(the actual jump should start as close to the portal as possible)
To reach a high place you need to be thrown into the portal by a vertical magnetic field
(diagonal in case of the second lift)
Jeff: below the steps after first portal jump
(jump into the portal with magnetic field pushing you from the right)
Required deaths: 2 one per circuit
Hang off the first lift to avoid the flame
You don't have to reset the circuit until the cup is unblocked
(jump off the raised lift into the diagonal magnetic field)
Tricks:

• Start the level when the camera pans to show the last room (then run left and jump without waiting for the camera or you'll miss the lift)

To turn off the flame you need to hit the button above the portal
Move the checkpoint by hitting the top button
(you'll need two ice cubes; two because you can't follow the first one into the portal)
To turn off the second flame, get an ice cube into the top chamber
Jeff: left
(use the lower checkpoint to provide unlimited freefall distance to an ice cube, then fling it across the gap)
Required deaths: 3 2x ice cube, reset triggers/ice cube
Technically you can do without a third ice cube but you need to respawn to reopen the portal anyway
Tricks:

• Reusing the second ice cube instead of making a third one saves you time for lowering/raising the frost generator
  
  • after you turn off the flame, let the second ice cube slide into the portal then turn it off and respawn on the other side – the ice cube will join you shortly
    
    • (somehow it only seems to work when I use the portal to reach that button instead of respawning there)
      
• In the first room: stack of 2 ice cubes → checkpoint+soul trigger → ice cube in portal → moving checkpoint + push 2nd ice cube left → jump off it before it hits the wall

Reusing the same undeath machine destroys a zombie (thus stopping it from pushing a button once you don't need it to)
Jeff: top left
(use a zombie as a trampoline)
Required deaths: 6 1st button, circuit, 5th button, 6th button, circuit, reset zombie
Press the second button yourself and help the zombie get over it into the circuit
Tricks:

• You can jump over the first flame using the zombie as a trampoline
  
• After you've activated the second circuit, don't touch the checkpoint on your way to the undeath machine

The first circuit needs to be activated by a zombie
Lead the zombie to the cart button by toggling the bridges as it crosses the ‘island’
Use zombies to remove corpses from buttons
Jeff: top right
(climb on top of the cart after you get it to move to reach him)
(you'll need to activate the circuit without touching the soul trigger)
(jump at the cutter wheel from the left so that the corpse falls into the hole)
Required deaths: 8 reset triggers, circuit, 3rd button, 4th button, 5th button, circuit, remove corpse, remove corpse
Tricks:

• Don't activate the last checkpoint until the gate behind it is open
  
• Turn on spikes on the cart as the zombie falls onto the button, then respawn and spike the knight before it leaves

You need a zombie to vacate the button after you stepped into the rotating box
To reach the cup you need to activate the top circuit but deactivate the bottom one
(activate the bottom one with a zombie then reset it)
Jeff: top left
(jump out of the rotating box as it turns)
Required deaths: 7 1st button, 2nd button, 1st circuit, 2nd circuit, 3rd circuit, 2nd circuit, reset zombie
Knock out a zombie on the 1st button instead of dropping a corpse on it
Climb out of the pit in the 2nd room by jumping off the zombie
Then jump off the top platform instead of using the spikes to climb
Tricks:

• Dropping a corpse on the 1st button is faster than trying to knock out a zombie
  
• You don't need to use the last button at all
  
  • (make a zombie before activating the bottom circuit, then run past the lowered wall as the zombie resets it)
    

Spike a zombie to the floor first
(after activating the circuit, spike a knight)
Most of the level is about guiding the zombie through it
The last circuit needs to be activated with a zombie; then reuse the same zombie on the button after it
Jeff: top left
(spike a zombie here too)
Required deaths: 7 2x spiked floor, 4 circuits on the way, buttons on the way/last circuit
Only 2 zombies are needed
An ice cube isn't necessary
(use the zombie as a trampoline)
Spikes on the gate aren't needed either
Tricks:

• RAISE ZOMBIE FIRST THINK LATER
  
• Technically it is possible to pass two doors as they close (the soul trigger trap & the last one) but only as a fluke

To let a zombie reach the bottom button you need to activate the soul trigger as a zombie passes the flames button
Then drop a corpse on the flames button and use the portal to place a zombie on each top button
(if you start with the top right button it won't reset if the corpse on the flames button was removed by a zombie)
Jeff: left
(zombies fall through rails)
(lower the right bridge yourself and use one zombie to lower the left one and let another zombie pass)
Required deaths: 3 flames button + both top buttons
You don't need the bottom button
(to reach the checkpoint platforms, just use a zombie as a trampoline instead)
(zombie from the top undeath machine can fall into the portal passage… or be helped to if you're impatient)
Also, jumping on a zombie from behind can make it stumble over a corpse
Tricks:

• Use the top undeath machine immediately then bump the zombie into the portal passage
  
• Then use it as a trampoline to reach the checkpoint above the button (from the slope next to the button)

Activate the 1st circuit with a zombie
You'll need a zombie to leave after hitting the rightmost button
(bump it from below to help it get across the gap)
Then you can block the flamethrower that resets the 1st circuit
(respawn to climb back – you'll need a zombie here, too)
Jeff: under the main passage
(capture a zombie with the soul trigger trap then open the door)
Required deaths: 5 top right button/footstand, 2nd circuit, top left button, 1st circuit, cup door button
You can reach the cup passage without activating the magnetic field
(use a zombie as a trampoline)
You don't need to respawn to get out of the bottom passage
(use the same zombie as a trampoline here too)
(some effort may be needed to stop it from falling off the platform
Tricks:

• Use the zombie trampoline trick for the cup passage
  
• Make sure not to squash the zombie with soul trigger gates as you activate the circuit
  
• Use the circuit again (after it's reset by a zombie) to respawn quicker

The boss checks your speed vector 3 times to aim – you can use this to direct his attacks
(he also aims at your last corpse before you respawn)
His attacks destroy your corpses
To reset the circuit on the 3rd cannon, make the boss shoot it
To hit the boss with 2nd and 3rd cannon, aim at the center of the portal
Most of the spiked floor in the last room is out of reach for the death ray
The death ray takes 3 souls to charge
It doesn't charge while it's shooting
The zombie in the last room won't be destroyed by death ray if it's near the left wall
For the last circuit, you'll need the death ray to reset it as you activate the soul trigger to pass
Jeff: below, after the 2nd cannon
(raise a zombie then distract the boss with a knight)
(die and don't respawn so that the flamethrower isn't activated)
Required deaths: 21
1. cup
2. spiked floor
3. attack
4. button
5. attack
6. button
7. reset trigger
8. circuit
9. button
10. attack
11-12. spiked floor
13. spiked wall
14-15. circuits
16. reset death ray
17. button
18-20. circuits
21. attack
You can use coyote time to cross the first spiked floor using just one knight
After reaching the middle checkpoint in the last room, reset the death ray (using spikes) then raise a zombie before it stops shooting
You'll reach the top passage with 1 soul left for the death ray so activate the circuit and do the final run
Tricks:

• After the 1st cannon, you can raise the moving checkpoint and respawn before it goes down
  
• If you shoot the checkpoint with the 2nd cannon before it's moved, the knight will bounce off the wall into the button

After you die several times on the Floor of Death, a trapdoor will open
Jeff: bottom right
(after 2nd circuit)
Required deaths: 13 2x spiked floor, trap, wall, boulders, trap, 4x floor, circuit, circuit, pillar
The trapdoor under the 2nd checkpoint is opened by dying beyond certain point – use coyote time to jump there
(jump specifically after running off the platform as you also need to make a low jump to avoid cutter wheels)
2nd boulder is triggered by being at a certain height: jump when you're about to be crushed by the 1st one
If you're mid-jump (at highest point methinks) when the 2nd magnetic field is activated, you can avoid the ceiling spikes
Supposedly you can also avoid the 2nd spiked trap but I couldn't actually manage to
(neither of these two are actually required for the challenge death count tho)

A speedrun of the game is a playthrough from start (level 1.1) to finish (level 5) in order without restarts (incidentally, beware of glitches such as respawning while being affected by magnetic field in which you died in Mind the Gap). If you enabled display of the timers (which is highly recommended if you're trying to beat the challenges, BTW), you can see the speedrun duration as a second timer when you start playing from the first level. Note that after you beat a level, the level selection screen will point at the next one you should play, so if you don't move it before starting the level you won't interrupt your speedrun.

Also note that if you're trying to get “Beat the Devs” achievement (complete a speedrun within ~46 minutes) you really should master each level first (except for bonus levels, you won't play them in a speedrun – note that the credits level is included), since you'll need to use as many tricks as possible to get it. In fact, if you manage a noticeable improvement over the challenge timer due to a trick like that, it's something that's gonna make beating the speedrun challenge that much easier. (Moreover, it appears that total challenge time of all levels combined is roughly equal the speedrun challenge time, so you really do need every advantage you can get – unless you're expecting to beat challenge timer on every level at the first try.)

When doing a speedrun, before running a level take note of the par timer as well as your achieved time – it lets you gauge how much time you can expect to spend on a level. The greater the par timer, the harder you need to work to minimise the time you spend on the level (and a noticeably lower achieved time means you can do it to a great effect). Use the tricks that improve the time significantly as long as they don't have a very low chance of success (as if you fail once you can usually try again once more to make up for the lost time, but failing twice probably means you lost the time for good). And, take the level preview time to refresh the level in your memory – unless you can greatly improve the level time if you start it early.

Here's the list of levels where you can (in theory) get a few extra seconds to make up for the time you'll overspend on other levels (because the best time on those isn't much better than the challenge time), along with reference total time you're supposed to reach by the end of each world:


Note that you aren't guaranteed to take these at your first try (these are my currently marked best times), so don't expect to just have an extra 4 minutes to spare without having to work for it. Still, these are the ones where the gap was no less than 3 seconds, so getting within a couple of seconds from your best time is probably good enough for most levels (though you still should try to get as much extra time as you can get from these). And I suppose you should make sure you can beat these levels within similar timeframes before going for a full speedrun.