Welcome to Debris 100% Achievement Guide

Debris is an atmospheric adventure game set in an underwater environment. The game is mostly exploration oriented with action elements but emphasizes on mental struggle and developing psychosis. This aspect of the game drawn me so much, I decided to make this guide.

To obtain 100% Achievements you will need at least four playthroughs.

More realistic number of playthroughs is five, if you play first time without spoilers and guides. Game is not too long, you can easily speed run it in 2-3 hours. There is a problem with two achievements and you won't be able to unlock them without additional device to run the game (only Steam Deck verified so far).

All achievements can be divided in four categories and almost all of them are MISSABLE :

1. Exploration
2. Danger
3. Montipora Logs
4. Ending

First part of the guide contains quick overview of all achievements, latter is reserved for in-depth walkthrough through each chapter with maps.

All achievements can be divided in four categories and most of them are MISSABLE :

1. Exploration
2. Danger Related
3. Montipora Logs
4. Ending Related


Videographer
Enable the scenic screenshot mode.
Press H few times to remove the HUD completely.

Jacques Couestau
Make your presence known in the Shock.
Shoot a flare towards fishes in Chapter 3

Over Here, Sonya!
Winner winner frozen dinner. Find the frozen fish.
Chapter 6, for precise location, check the map in walkthrough section.

Thrusters Disabled
Do you trust ALTA?
Unmissable. Answer to Chris first question in Chapter 6 by moving forward or backwards.

Ryan..
Not all voices are against you. Find the Hall of Voices.
Chapter 8, for precise location, check the map in walkthrough section.

Thrusters Enabled
Let's hope you're right.
Unmissable. Answer to Chris second question in Chapter 8 by moving forward or backwards.

Choking Hazard
Find the dead fish who ate an urchin.
Chapter 9, for precise location check the map in walkthrough section.


Safe Passage
Make it through the dark fish delta in Dark without taking damage.
Make it through section with glowing fish in Chapter 5 without taking damage. Shoot them with spears to move them if needed.

Chumless
Make it through Light and Teeth without taking damage.
Make it through section with sharks in Chapter 7 without taking damage. In depth strategy in walkthrough section.

Minesweeper
Make it through the Bobbit lair without taking damage.
Make it through section with worms in Chapter 8 without taking damage. In depth strategy in walkthrough section.

In Flow
Make it through the dark fish delta in Flow without taking damage.
Make it through section with glowing fish in Chapter 11 without taking damage. Shoot them with spears to move them if needed.


Memory Leak
Find a secret irradiated montipora and dive into ALTA's archives.
Find one Montipora (Chapter 2 is the first location)

Overflow
Find half of the secret montipora.
Find at least 12 Montipora in one delusion (playthrough).

Submersion
Find every secret montipora throughout the cave network.
Find all 24 Montipora in one delusion (playthrough).

Sunk
Complete the montipora archive in every reality.
FInd ALL Montipora in ALL 4 delusions.

This means that you need to finish the game 4 times, each time with a different delusion, while finding ALL Montipora. Hardest achievement in the game.
However, doing this has its own flavor rewards, because Montipora logs change depending on the state of your current delusion. Until first branching in Chapter 6 - Choice, all Montipora are the same. Depending on what choice you made, from this point all Montipora has 2 different variants. And after second branching all Montipora has 4 different variants.
There is total number of 63 different messages to be found and this achievement requires them all.

Submersion and Sunk achievements are actually bugged.
Those achievements won't unlock in a regular way even when completing the game four times with all Montipora logs checked. Achievement progress counter will get stuck on 23/24 for Submersion and 62/63 for Sunk.
Thanks to user Anxiety it is known that the game needs to be installed and started on some other device (ie Steam Deck).

You only need to play 5 minutes to reach first Montipora in Chapter 2 which will trigger both achievements.



Different endings and different storyline is affected by answers you give to Chris on two occasions. Since we answer by moving our suit forward or backwards and have two branching moments, there is a total of four different combinations for game to play out it's course.

Escape
Do Not Die Alone.
Complete the game.

Grandiosity
Endure a grandiose delusion.
Complete the game with Grandiosity delusion (forward/backwards).

Persecution
Endure a persecutory delusion.
Complee the game with Persecution delusion (backwards/forwards).

Control
Endure a delusion of control.
Complete the game with Control delusion. (forward/forward)

Somatic
Endure a somatic delusion.
Complete the game with Somatic delusion.(backwards/backwards)

Reality Check
Endure each delusion.
Complete the game four times each time with different delusion.

Some players reported that achievement did not trigger for them, even after completing the game with all four delusions. It is advisable to use a new save slot for each new game, which will allow you to keep Level 15 saves for all delusions. If achievement has not been rewarded naturally, recommended solution by user Toastbubbles is to play again all 4 delusions from Level 15 save slots - IN ONE SITTING. This does not require a lot of time, so be sure to keep your saves just in case.

Chapter 1 is short introductory animation, we have no control here.

Follow the instructions and get used to controls. Notice that ocean's underwater current greatly impacts your movement freedom. This is of utmost importance later in the game.

Keep following the water current and soon we will find our first Montipora log. Montipora's are mushroom-like plants that impacted by Debris, developed ability to store messages sent by ALTA scientists and divers in new experimental suits. When you approach Montipora, you can listen to parts of this "trapped" messages and get better understanding of the events that took place before the game.
When Ryan sees the fish and glowing corals he will start a conversation with Sonya. Montipora is on the left tunnel on intersection. Montipora locations are marked on maps with yellow dots.

Keep following the current to meet up with Sonya. A fish will chop off your suit light and you will chase it to a clearing where you will meet up with Squid ROV, instead of Sonya. It turns out that Sonya is stuck elsewhere and she is remotely controlling the Squid - which will be essential to your survival.

Squid has the ability to harness the Debris and turn it into operational minutes of power (MP) for your suit. Same power is used for sustaining life, as well as using Tool - which we will get later. Squid uses MP too and it's remaining power is always visible on your HUD. Furthermore, if one of you gets low on power, you can equalize, by pressing the action button E when near the Squid. This means that your remaining total power will be evenly distributed to ensure equal chance of survival. Sometimes you will have to save Squid, more often you will need saving. If any of you runs out of power, game is over.
Don't forget to harness all Debris you see. Squid will sometimes skip the Debris and move on or wonder around for no reason, so you need to call it by pressing the button Q.
Maximum power your suit or Squid can store is 75 minutes.

Follow Sonya along the route and pick up the Tool.
Tool is a fancy new gadget that Sonya developed and has two operating modes : shooting flares or spears. Both of them consume power (flare - 1 minute of power, spear - 3 minutes of power). If you need better light, just switching to Flare Mode will provide some basic illumination (without spending power by shooting flare).
Learn to use your Tool sparingly, because power can be very very scarce, especially later in the game.

If you already didn't do it, now is the good time to press the button H and unlock the achievement Videographer.


Move on to the next cave and pick up a Montipora log in tunnels on the left. Proceed to the last big cave in this chapter. You will encounter fishes that are attracted by light - Flare Eaters - one of them already attacked you before and stole your suit's light.

Shoot one flare towards fishes to unlock achievement Jacques Couestau.
Fish will swallow the flare and die. You need to get rid of all of them because they will keep attacking you and a Squid, draining your power. Always launch flares in front of fish movement direction, so it can pick it up easily.

After dealing with Flare Eaters pick up next Montipora log on a reef, bit tricky to find, then proceed further into tunnels dealing with attacking fish along the way.

Start off by killing the new enemy - Guardian - by using the Spear mode on your Tool that Sonya just unlocked for you. Shooting one Spear drains whooping three minutes of survival, so you need to make your shots count. Guardians will attack you and drain 3MP wit their bite. They are usually found circling around Debris deposits. That means you will need to invest some power to gain more. Always pick up ALL Debris that you stumble upon, starting with this first Debris pool you encountered. It can get really rough later in a game. Additionally, Watch out for spiked plants, because they can hurt you on contact draining 4MP.

Move on through the chapter collecting Debris until you find next Montipora log. Notice that current can pull you towards the level progression, skipping this lightly hidden area. Fighting with currents is something Ryan will have to do a lot later.
Soon after you hear Chris mumbling on the radio you will enter bigger cave which contains large Debris deposits. In this cave is next Montipora log.

Proceed to next bigger cave repeating the same pattern and pick up third Montipora log in this chapter at the cave's end. Make sure you take a right tunnel on the intersection or you will skip it. These tunnels are actually lair to Bobitt Worms. They can deal a lot of damage and can't be hurt with a Tool, so you need to avoid them at all costs. This first encounter is fairly easy, just don't go too fast and follow the current. Important to remember is that Bobitt worms need few seconds after attacking to "recharge" their attack. This fact will be key for our survival later.
Proceed towards chapter end repeating the same patterns.

At this point, third mission member - Chris, has found the other ROV named Jellyfish. Using Jellyfish Chris can track our location on map. Chris can talk to us but can't hear us because of equipment failure.

After hearing Chris, we will approach tunnels with big glowing fish. We need to stay clear of them because they deal 10 MP damage on contact.

Making through this Chapter without receiving any damage will award us the Safe Passage achievement. This task is not too hard as you can always use your spears to move them a little. However they cannot be destroyed.

There is some growing Jellyfish on this level which should be avoided too. Jellyfishes deal 15 MP damage on contact, so pay attention.

Proceed through the tunnels picking up two Montipora logs marked on map. Meanwhile, Chris has gained ability through Jellyfish ROV to control your suit. He will stop your suit from moving and ask questions on which you can reply by moving forwards or backwards. That way Chris will have some feedback from you.

In the last section you will have to dispose some Flare Eaters, watch out, they can rush your ROV very quickly.

Start off by eliminating some Guardians and collecting Debris along the way. After Chris makes his monologue you will enter narrow tunnel with Jellyfish.

Take sharp turn downwards and continue until you reach the bottom. On the wall, there is a frozen fish which can only move its eyes. This discovery will get you Over Here, Sonya! achievement.











Get back in the tunnel and proceed further eliminating guardians and collecting Debris. Chris will continue with his theories about ALTA trying to eliminate you. Among the Guardians you will encounter Big Guardian for the first time. It follows same behavior pattern as regular, although it is much bigger and requires two hits with a Spear to eliminate.
Soon you will spot a giant fish which is the main subject of a possible Persecution delusion. You will also hear cracking sound this fish supposedly make.

Which delusion Ryan will endure depends on choices made while answering Chris questions.

This bigger cave is the place where is located only Montipora in this chapter. Soon, after moving forward Chris will block your thrusters and ask you if you can hear him. Go backwards to progress the story, if you troll Chris by pushing forward you could probably bug your playthrough. Real choice related question is soon to follow.

Near the end of the level Chris will block your thrusters again and ask you what is a bigger threat : ALTA or Debris.

This is the key point in the game.
If you chose to go forward (and support Chris theories about ALTA as main threat) Ryan is on a path to evolve Grandiosity or Control delusion. If you go backwards and mark Debris as a main threat Ryan could evolve Somatic or Persecution delusion.

From this point in the game all Montipora logs will differ regarding which choice you made. They remain in the same place, luckily.
Make your choice to conclude the chapter.

At the start, we will come across glowing thorns. Glowing thorns can't hurt Ryan and offer great protection from predators, especially from Sharks.
Sharks are new enemy and along Bobitt Worms - most dangerous one. They deal 11 MP damage on contact. When shark locks Ryan or Squid it gets green glow, eventually turning red when it's really near. Minimap is very useful to track down attacking Sharks that are approaching you. Dealing with sharks has two obvious options : avoid or kill. You can't run from them because they are much faster. They can be eliminated with 3 spears, which cost 9 MP per shark. They often patrol in groups of 3-4, so this solution is reserved for situations when there is no other safe option. Sharks avoid all types of light, so the best option is to evade them using environmental layout, or using cheap flares to make artificial illumination.

Unlocking the achievement Chumless requires making through this section without being hit. If you get hit, reload the last saved checkpoint and try again.


Strategy for safe passage through this area :

In the first chamber just follow the obvious path along the right wall hiding behind glowing thorns.
In second chamber repeat the same strategy.
In third chamber hug the right wall again until you reach a gap in glowing thorns placement. Don't make a run here as Ryan suggests. Better option is to hug a right wall and periodically shoot some flares in it, while moving. You can shoot flare directly towards the Sharks, too.
Fourth chamber will have some debris to replenish power, deal with Flare Eaters first.
Fifth chamber will start with glowing thorns barrier with three sharks patrolling behind. Best course of action here is to take them out. After that proceed straight through the cave until we reach an opening with more sharks. All we have to do is hug the left wall and proceed to the cave exit. One Flash Eater will charge the Squid so be prepared to take it out quickly.
In sixth chamber shoot some flares along the right wall and stick with it. You should soon reach the area with some Debris and the only Montipora log in this chapter. Again, hug the right wall as long as you can because it will take you almost to the chamber's end completely bypassing all the dangers. I wrote ALMOST here with a reason, because the hardest part is left for the end. You need to gap a big area and right wall is risky because it's much longer way and sharks patrol route is very near. Best option here is to make a run straight across the chamber towards glowing thorns and safety. Use strafing movement and keep your eyes on the sharks. When sharks lock on you, shoot it directly with a Flare. Flares are cheap and it will deaggro the shark completely. Flare Eaters can attack from behind, make sure before you start your run that area is clear of them.

Best route for the sixth chamber is marked on the map.

Chapter 8 is going to be very intensive.
Charge up on as much Debris as you can while moving forward through first caves. At one point Ryan will reach a huge opening which is a massive Bobbit worm lair. This time they attack from the ground instead of walls and are significantly more dangerous, mostly because their numbers and density is HUGE.

Bypassing them is out of question, they are everywhere. Whole area is basically a minefield. To make things even harder, we must move through entire lair without being hit to unlock the Minesweeper achievement.

This is the hardest chapter in the game.

Good strategy is to move along the route with lowest worm concentration using the trigger flare method. As i mentioned before, their attack has a few seconds cooldown. After triggering their attack with a flare, wait few seconds for them to retreat to the ground and then move on. Waiting for too long will make them attack again and hit us, but rushing forward before they retract their claws will hurt us too. So, our moves need to be timed perfectly. This is not an easy task and requires some practice, because of the worms density. Most of the time you will simultaneously triggering groups of them in front of you, dodging those on sides, while running away from those below and behind you. The water current isn't helping because it doesn't allow you to stand still and plan your moves.
Best route is marked on the map.
Move forward across the first recession luring 3 worms, then 2 in second recession. Third recession is empty but after this point worms are everywhere. Shoot many flares forward and take a left turn when you reach bigger recession split in two. Head for the Debris deposit. After collecting debris, look around to locate another Debris deposit across yet another big recession. Cross it and you reached safe zone. Replenish your power level with Debris. Move forward and achievement will soon be rewarded.

Before proceeding to next section, look closely on the map provided and make a detour to pick up Montipora located nearby. Then turn around and move to next section, which is inhabited by sharks. There is a lot of Sea Grass in this cave which sharks avoid and it's harmless on contact. Sea grass is not to be confused with Spiked Plant mentioned before which can hurt Ryan.
Good strategy is to somewhat ignore the Sea Grass and go for the Montipora nearby. After picking it up, hug the right wall and move to the end of section. There is a big dead end cave on your right, so check the map and don't enter it. If some of the sharks notice you eliminate them, power level should be high after replenishment in worm's lair.

Moving along, Chris will again stop our thrusters and ask us a question. If we marked ALTA as a threat before, we can choose between switching off AI on Jellyfish ROV (Control ending) or shutting ALTA sensors off (Grandieur ending). If we marked Debris as primary threat earlier, we can choose between (Somatic ending) and (Persecution ending).

Last cave system in chapter is called Hall of Voices. Move through it to unlock Ryan.. achievement. Dive around the cave and near approximate location marked on map. Achievement should pop at some point.

Start by moving forward to trigger conversation between Ryan and Sonya about dead fish. Then, turn left and move to the far end of the cave to pick up Montipora. Watch out, because there is a single Bobbit worm lurking near Montipora

Move forward along the left wall to the end of the cave to reach the area with more dead fish. This area needs to be examined to unlock the Choking Hazard achievement. Be careful, a single Bobbit worm is waiting behind fish.

Cave is inhabited by Flare Eaters who may attack you or the Squid, so be prepared to eliminate them. Don't let Squid wander too far.

Upon entering underwater forest patrolled by sharks, try to stay as low as possible and move through the trenches. However there is one Montipora on the far left side of the cave. Best and cheapest strategy would be to avoid shark as much as possible and scare them off with flares if needed. If they are coming from multiple directions, shoot one flare into the seabed and hang on there until they turn around.
Move quickly, pick up Montipora, leave the area.
There is a high concentration of sharks near the end, so make sure you save enough power for flares.

After leaving the dangers of the woods, Ryan has to navigate section with strong currents. This is being done by using trenches as long as it's possible. Stay low and navigate from trench to trench using the narrow passage visible on map. Make sure you pick up all Debris along the way.
There are two Montipora locations, second one being somewhat tricky to approach. Frequently consult the map provided. If the current pushes you too far, there is no going back to Montipora location. So you have to make it in first try. When you reach the last trench, turn left and go to the end staying very low.

After picking up Montipora, eventually the current will pick you up, it's unavoidable and you will approach the section in which glowing fish have to be dodged again.

Navigate glowing fishes without damage to unlock the achievement In Flow. This time it's more difficult as the current carries you very fast. Getting hit drains 10 MP, but you can always shoot a spear to move the fish if collision seems unavoidable.

Upon entering next cave Ryan will have delusion episode, which is different across playthroughs and based on choices you made earlier, but ultimately can lead to same outcome - death. You need to wait and not approach the Debris deposit until Ryan comments that it's safe to do so. Proccess the Debris and move on to conclude the chapter.

The current which carries Ryan is still very strong and it will limit Ryan's movement through most of chapter. That makes it hard to pick up next Montipora even if you know it's exact location using the map provided in this guide.
After stocking up on Debris, current will pick you up and you need to hug the left wall. Progress through the cave, checking the map frequently, so you don't miss location where you need to take sharp left turn and use your thrusters to very slowly progress to Montipora location. Don't let the current pull you. Change direction and angle of movement, do whatever it takes to start progressing against the current. When you finally reach Montipora, sometimes Ryan won't stand still above it and listen entire log message, unless you navigate him.

After reaching Montipora location, get back on main route and progress through the cave. Upon reaching chapter's end you will have to avoid giant Jellyfishes and enter the tunnel on right wall to move on.

Move forward evading the giant Jellyfishes, each contact will deal 8MP damage. Soon you will notice groups of sharks patrolling. Stick to the Jellyfishes, because sharks wouldn't dare approach them. Upon entering second cave Ryan will stumble on another group of sharks. Eliminate all four of them in order to safely reach Montipora location nearby. Proceed further along the seabed to safely navigate jellyfish colony. Third cave will have some clear space between jellyfishes, patrolled by sharks. Aggro the sharks, but wait for them near the last jellyfish. As soon as sharks de-aggro themselves, make a run for a second colony.

Soon you will approach a jaw-like cave entrance. Be prepared, because 6 Flare Eaters will charge the Squid. Dispose of them and enter the Jaw on location provided on map. Stock up on the Debris to get ready for last section. There is a lot of stronger Flare Eaters which need to be hit two times with a spear. (they will be attracted to flare and die upon swallowing it, but sometimes they ignore it and go for the Squid). If you wander around this area too much and engage a lot of them, Ryan will quickly run out of power. Best course of action would be to follow the exact route marked on map. It will minimize the encounters and allow you to pick up Montipora log on the way. Critical part of the journey is right after picking up Montipora log. There is a well hidden tunnel that will allow you to move forward without entering the main middle section of the cave. Use flares, check the map and take your time. Tunnel route is marked with green line on the map provided. After this just proceed further hugging the left wall, dispose of three enemies along the way.

After reaching Chris and the Jellyfish the current will drag you further. You can't help him no matter what you do.

Ryan needs to traverse three huge caves full of enemies. Since we have to pick up five Montipora logs, best strategy is to kill the guardians and sharks picking up the Debris along the way while avoiding huge fish which can't be killed. Notice that Guardians are now bigger and need two shots to be eliminated. Huge fish won't track you down, unless you go really close to it.
Plan your routes carefully, since the current is strong and backtracking can take a while, although it is possible to swim back and visit all missed locations.

At this point Ryan's delusion will be in it's final stage, so expect various malfunctions regarding your vision and movement.

First cave will have two Montipora, near the exit. Easy to avoid all dangers.
Second cave contains one Montipora, if you use the shortest route to exit after picking it up, using the map provided, expect strong current against you. It is a slow progress, but safe one.
Third cave will have two Montipora, go right as soon as you enter the cave and pick up the first near the glowing fish. Then go straight accross the cave for second Montipora, avoiding big fish.

While picking up Montipora log, make sure you clear enemies and stock up on Debris regularly.

After picking up all five Montipora, leave the area.

Move forward and hug the left wall. Progress the story towards the end, despite problems with vision and movement. After reaching the certain point current will pick you up and pull you towards the surface.

Ryan managed to escape.

I hope you enjoyed Debris story as much as I did. My first playthrough had Somatic ending. At the end I was "sure" that Ryan was already dead xD.

From each of us, game manages to extract worst fears when faced with similar threats to our survival. So everyone develops his own psychosis. Great concept.

Achievements are really hard to obtain and consume a lot of time. Buggy Montipora achievements are making this task even harder.

I would be honored if this guide helps you make it to another 100%. I put a lot of time and effort to make it, it would be really nice if someone actually used it xD.

Thanks for reading!