I am constructing this guide as I go. I Don't know the best tower types or the best upgrades or what to pick on each map. This is just me doing my best to help other people. Hopefully you'll find something helpful in this guide.

Before we get into the parts and bullet casings, I want to go over what each stat does so everyone is on the same page.

Health: This is how damage a turret can take before being destroyed. Turrets can be rebuilt via an ability, another tower, and are fully reconstructed at the start of the next wave.

Damage: How much each shot from a turret does to a creep before any armor values.

Damage per second (DPS): Total damage that happens in one second. This is calculated by taking the damage number and multiplying it by the fire rate.

Fire rate: How many shots it can make in one second.

Aim speed: The max speed a turret can rotate on it's Axis.

Range: How far a turret can target a creep. Note that 1 equals one tile.

Upkeep Tax: This is how much of a burden it is to maintain the turret. Every time you gain money, a portion will be deducted depending on how high the tax is. You cannot build any more turrets if the tax reaches 60%.

Strength: What this turret is most effective at.

Weakness: What will overwhelm this turret.

I'll go over each turret in the order you unlock them. I'll start with its name, it's in-game description, stats and their upgrades, then give my final thoughts.

Blaster

A fast-firing mid-range turret. Often used to make living things dead

Cost: 120
Health: 500/1000/2500
Damage: 25/35/45
DPS: 50
Fire rate: 2/2.5/3.25
Aim Speed: 310
Range: 6/7
Upkeep Tax: 0.6%
Strength: Fast
Weakness: numerous
Upgrade cost: 60X(# of upgrades+1)

Your basic turret you find in every tower defense. Its damage upgrades almost double each shot's damage and the rate of fire is not insignificant. You can also upgrade it's health to 2500 if it's going to be the first target along your path. The turret can also get a cloak detector, letting it target invisible enemies. It's range isn't worth upgrading as the max is seven tiles. I recommend maxing out it's fire rate and damage to help it deal with weaker creeps and have it target the fastest.


Wall

Use it to block things you don't want to get from one side of the wall to the other side of that same wall. Walls are indestructible, and turrets can be built on top of them.

Cost: 15
Upkeep tax: 0.1%

I know this isn't technically a turret but I felt it needed to be included anyway. Walls are good for extending your death maze and can be use to destroy creep eggs that spawn, thus limiting the resulting swarm. That being said, be careful where you place them as they still drain you funds and those disappear quicker than you think. They also can block Line-of-sight on your turrets, limiting their effectiveness. Turrets also don't benefit from a range boost as their range is a sphere effectively.

Artillery

Fires explosive shells across a long distance, doing damage to those unfortunate to be within the blast radius Artillery cannot target units that are too close. Shells may damage friendly units slightly. Needs adequate overhead clearance.

Cost: 225
Health: 1000
Damage: 45/55/75/100/140
DPS: 9
Blast Radius: 2.25/2.5/2.75/3.25
Fire rate: 0.2/0.22/0.24/0.28
Aim Speed: 25/45
Range (Min/Max): (8/18)/(8/22)
Upkeep tax: 1%
Strength: Numerous, Slow
Weakness: Strong, Fast
Upgrade cost: 100X(# of upgrades+1)

This thing is excellent against swarms of creeps. Damage can be upgraded all the way to 140 damage per shot and the number of projectiles can max out at 3, making any area it targets a no creeps land. The blast radius can be upgraded as well along with it's fire rate, aim speed, and Range. Those last few aren't as important as damage and projectiles are. It's recommended you max out projectiles first then damage and, if you have the credits to spare, blast radius and leave it set on minimal rotation.

Splatter gun

Fires a wide spread of small, explosive bullets. Ineffective at a distance, but it can chowder multiple creeps at close range.

Cost:180
Health: 500/1500/4000
Damage: 25/30/35/55
DPS: 62.5
Projectiles: 5/6/8
Blast radius: 0.35
Fire rate: 0.5/0.65
Aim speed: 180
Range: 5.5/6/7
Upkeep tax: 0.6%
Strength: Slow, Numerous
Weakness: Strong, Fast
Upgrade cost: 80X(# of upgrades+1)

This turret is excellent against a hoard, letting it heavily damage or outright kill anything nearby. Its projectiles can max out at 8. Combine that with it damage fully upgraded and it will see no creep slow enough gets past. Its health can be upgraded to 4000, making it a great front-line turret. I don't recommend upgrading its range as it is a shotgun after all, and the fire rate is nothing to write home about.

Ground Pounder

Periodically drives a massive weight into the ground, generating a small, yet unpleasant blast wave.

Cost: 340
Health: 1500/2500//7500
Damage: 25/35/45/55/75/100/150
DPS:12.5
fire rate: 0.5/0.6/0.75
Range: 2/2.25/2.5
Upkeep tax: 0.6%
Strength: weak, slow, numerous
Weakness: Fast, strong
Upgrade cost: 150X(# of upgrades+1)

This is not a good turret. Its range is abysmal and the fire rate is very bad, even when upgraded. I've managed to get some use out of it by having creeps make turns around it but it will only get a few shots off before the creeps are out of range. It's also expensive to build and upgrade. Thankfully it attacks automatically every time it's ready so it can hit cloaked creeps. It works well early on but it doesn't scale well against later waves.

Lag Field

Creeps within range of the Lag Field will become sluggish and lazy, or maybe even totally motionless for a short time. The lag field can also detect cloaked creeps for some reason. Slows targets down for a time. Freezes targets in place for a time.

Cost: 300
Health: 2000/3000/7500
Range:2.25/2.5/2.75/3.25
Freeze chance: 1%/2%/3%/5%
Upkeep tax: 1.2%
Strength: Numerous, fast
Upgrade cost: 125X(# of upgrades+1)

This is the first support turret you unlock and, for its price, is pretty good. Its range isn't great but that's fine because it gives the other turrets more time to do their job. It pairs great with AOE weapons like the Artillery and Splattergun since it groups creeps up. I would uprgade its range first than health. I almost never upgrade its freeze chance since that's random. Although you would improve it's odds, I wouldn't count on it stopping the most threatening creep at the time.

Ranger Turret

A powerful cannon that can take cheap shots at creeps from a cowardly distance. Not even cloaked creeps are safe. Bullets can pass through multiple creeps and shields.

Cost: 360
Health: 2500
Damage 350/450/550/800/1300/2500
DPS: 50
Blast radius: 0.35
Fire rate: 0.2/0.22/0.24/0.26/0.3\
Range (Min/Max): (6.5/20)/(6.5/24)/(6.5/30)
Aim speed: 35/55
Upkeep tax: 1.2%
Strength: Strong, fast, singular
Weakness: Weak, numerous
Upgrade cost: 140X(# of upgrades+1)

This turret is basically your boss killer. Have it target the strongest and upgrade its damage and range to maximum. Its fire rate and aim speed upgrades can make a difference but not very much.

Beam emitter

The beam does progressively more damage the longer it fires on a single target. Once it fires, it will never stop unless line of sight is broken, or its target is vaporized. Do not look into the operational end of the device.

Cost: 150
Health:500/1000/3500
Damage: 8/10/15/20/35/65
DPS: 8
Fire/Charge rate: Scales forever
Range: 8/9/10/12
Aim speed:225
Upkeep tax: 0.6%
Strength: Strong, Slow, Singular
Weakness: Fast, Numerous
Upgrade cost: 60X(# of upgrades+1)

This isn't a terrible turret for it's cost but it's not the best. Its cheap to build and upgrade and great against tougher creeps like Bricks and Bosses but the damage only happens every second, not over time. As far as I can tell, as long as it has a lock, the damage will scale forever but will reset every time it targets a new creep. Additionally if it can't see it's target but is still within range, it will hold its lock for a second and a half before switching targets, letting it keep its high damage. I recommend maxing out its damage first then range then health.

Pulser

Fires slow travelling magnetic plasma bolts that dish out huge amounts of physical and emotional damage. Bullets can pass through solid objects.

Cost:210
Health: 600/1500/5000
Damage: 75/100/150/200/400/800
DPS: 52.5
Fire Rate: 0.7/0.8/1
Range: 5/6
Aim Speed: 140
Upkeep tax: 0.6%
Strength: Strong, Slow
Weakness: Fast, Numerous
Upgrade cost: 85X(# of upgrades+1)

This turret is a better choice over the Beam Emitter for several reasons; it doesn't need to scale it damage over time, its shots can go through your turrets without damaging them, and they can re-target if their initial creep dies. However, it's still limited by line-of-sight and doesn't perform well against faster creeps as they can outrun its shots. It's more expensive overall but The Pulser is well worth the investment. I recommend maxing out its fire rate than damage, Health first if it's near the front.

Boost Emitter

Boost the effects of nearby turrets and structures. And yes, boost effects can stack. Just don't expect to boost other boosters.

Cost:560
Health: 1500/2500/3500/7500
Boost; Damage: 1%/10%/20%/30%
Boost; Fire rate: 1%/10%/15%/20%
Boost; Range: 1%/10%/20%/30%
Boost; Repair: 0%/0.1%/0.2%
Range: 1.5
Upkeep Tax: 1.4%
Structure Limit: 5
Upgrade cost: 200X(# of upgrades purchased+1)

I wouldn't recommend this as the initial cost is expensive and you need to purchase an upgrade for it to actually make a difference. Also, the range is very short as in, you have to place turrets right next to it for them to be affected. Its odd shape does let it be built in places where turrets won't be most effective. If you do end up getting this, however, I recommend never upgrading its health because, with other turrets nearby, creeps will more important things to worry about.

Snap Trap

Unlucky creeps that spring the trap are shanked by a wall of spikes. Not even cloaked creeps can sneak past. Takes some time to rearm. Charge capacity can be upgraded, allowing the trap to trigger in rapid succession. Can not be built on walls.

Cost:285
Health:1500/2500/7500
Damage:200/250/350/500/1250
DPS:50
Charge/Fire Rate: 0.25/0.35/0.55
Charges: 1/4/8
Upkeep Tax: 0.6%
Strength: Strong, Fast
Weakness: Numerous
Upgrade cost: 120X(# of upgrades purchased+1)

This trap is actually pretty good against clumps of enemies as it will hit all enemies on the tile it targets. However, even maxed out its slow fire rate prevents it from being part of the front line. This kind of trap is better suited near the middle or rear where it can store up charges for the creeps that make it through the initial grinder. I would also recommend upgrading its damage to help it deal with boss creeps.

Toxic launcher

Infects unvaccinated creeps with a powerful toxin that will slowly eat away at their ability to live. Poisons targets, doing damage over time. Does nothing to shields. Total poison limited by creeps MAX health: 75%

Cost: 380
Health: 1000/2000/7500
Damage: 100/150/250/500/1000
Blast radius: 1.2/1.4/1.6/2
Fire rate: 0.35/0.5/0.8
Range(min/max): (2.5/4)/(2.5/4.5)/(2.5/5)/(2.5/6.5)
Aim Speed: 275
Upkeep tax: 0.6%
Strength: Strong, Slow
Weakness: Fast, Weak
Upgrade cost: 130X(# of upgrades purchased+1)

The Toxic launcher is essentially every social media site if it was a weapon. It's a good front line turret, provided it's far enough away to deal damage. The limit does prevent it from killing creeps outright but it will take care of any creeps that have less than three-quarters of their health remaining. It wouldn't be my first choice but its a fine addition to your arsenal. I recommend upgrading its damage and blast radius first then its range and fire rate.

Mini-You Fabricator

Builds and maintains a single adorable tiny version of Brian Jar. Mini-You can freely float anywhere on the map, looking for creeps to pester to death. Needs to return to its fabricator to rearm.

Cost: 200
Health: 500
Damage: 30/35/40/50/75/150
DPS: 48
Fire Rate: 1.6/2/2.8/3.4
Range: 6.5
Ammo: 100/200/500/1000
Drone Health: 75/100/150/250/550
Upkeep tax: 1.2%
Strength: Singular, Slow
Weakness: Numerous
Upgrade cost: 100X(# of upgrades purchased+1)

This is one of the more unique and versatile towers in your arsenal. The myriad of upgrades allow it to fill gaps in your defenses. If you want it to target faster creeps, upgrade its ammo and fire rate. Want your boy to be a big game hunter, boost his health and damage. They even can have a cloak detector, letting your kids hunt down any sneaky creeps that make it through your defenses. I do recommend upgrading its ammo count first on larger maps cause they will have to make the journey back to their room every time they need more ammo.

Chain Bolter

Fires an electrical bolt that can pass on to other nearby creeps, linking them together into a chain of pain. Inflicts random damage between one and max. Damage to shields: 200%

Cost: 380
Health:1500/2500/7500
Max Damage: 150/175/200/300
DPS: 187.5
Fire rate: 0.25/0.35/0.55
Range: 3/4/5
Arcs: 10/11/12/15
Upkeep tax: 0.6%
Strength: Numerous
Weakness: Strong, Singular
Upgrade cost: 175X(# of upgrades purchased+1)

This is a really good tower despite its random damage output and high cost. The tower's initial target just needs to be in range and the Arcs will hit any other creep within one tile.The lightning doesn't seem to be able to hit the same creep twice on the same shot though and its slow fire rate holds it back. I recommend having it target the weakest creep and maxing out its rate of fire first then damage.

Flame Turbine

Shoots out a jet of fire along a set path. Most living things don't like being burned. Sets targets on fire, damaging them over a short period. Burning creep speed: 200%

Cost: 275
Health: 1500/2500/7500
Damage: 80/120/200/450
DPS: 32
Fire rate: 0.4/0.45/0.55
Range: 4/4.5/5/6
Upkeep tax: 0.6%
Strength: Numerous, Slow
Weakness: Fast
Cannot be built on walls
Upgrade cost: 85X(# of upgrades purchased+1)

The turbine is another trap weapon that auto fires. I wouldn't recommend this one as while fire does decent damage, it also doubles the creeps speed, making faster creeps like the runner blitz through your defenses. You can make an argument of fire is useful but it can also be argued that it also limits how much damage your turrets can get in before the creep reaches the drill. I recommend upgrading its fire rate and damage.

SRM Launcher

Short range missiles can track targets, making them nearly impossible to avoid. Freshly launched missiles take a short time to lock-on, but once they do they accelerate toward their victim at ludicrous speeds! Needs adequate overhead clearance

Cost: 450
Damage: 40/60/80/120
DPS: 48
Projectiles:2/3/4
Blast radius: 0.4
Fire Rate: 0.6/0.8/1
Range (Min/Max): (4/12)/(4/14)/(4/16)/(4/20)
Aim Speed: 180
Upkeep tax: 0.8%
Upgrade cost: 185X(# of upgrades purchased+1)

This is an excellent weapon as the multiple projectiles let it take out most creeps in one volley. The missiles can retarget mid-flight if the original creep is kill before all the missiles hit, even if the new target is inside its minimal range. The blast radius does help it somewhat against groups but its better to have this weapon target the most dangerous creep in range. I recommend maxing out its projectiles then its damage or rate of fire.

Medic hub

Builds and maintains single Medic Drone. Medics can float anywhere on the map, fixing damaged structures and helping out with construction tasks. Needs to return to its hub to recharge. repair rate is based on targets max health.

Cost: 240
Health: 750
repair: 1000/2000/5000/10000
Mini-Health: 150/250/550/1000
Repair Rate: 5%/10%/15%
Upkeep tax: 1.2%
Upgrade cost: 80X(# of upgrades purchased+1)

This support tower is better built in the later stages when the sweepers and boomers and such start marching. I do recommend upgrading the drone's health by one or two levels than max out with its repair rate or how much it can restore depending on how big the map is.

Laser gate

Creeps that pass through the Laser Gate are punished with electricity! Passing creeps cause a feedback surge, increasing the damage output for a brief period. Beware, if the surge gets too high, the Laser Gate will overload and explode! Inflicts random damage between one and max. Damage to shields: 200%

Cost: 380
Health: 1500/2500/7500
Damage: 50/75/100/200/450
Upkeep tax: 0.6%
Strength: Fast, Numerous
Weakness: Singular
Upgrade cost: 165X(# of upgrades purchased+1)
Cannot be built on walls

This one is an interesting design as the ramping damage makes it great against hordes but that does run the risk of destroying itself. I'm unsure how a cloak detector benefits the gate as I'm sure it will damage any cloak creeps that pass through it anyway. I don't recommend having this as the first line of defense as it will be overwhelmed. Place after a few turrets before it, upgrade its health once than max out its damage.

Chrono Ray

Opens a crack in space-time and shoves a creep through it. Victims end up at an earlier point on their journey, so they can experience part of your death maze a second time. Paradox Prevention 101: You can only send creeps through time once. Sends targets to where they were in the past (once)

Cost: 700
Health: 1500
Distance: -14/-18/-22/-28
Duration: 5/4/3
Fire/Charge Rate: 100%
Range: 8.5/9.5/10.5/12.5
Aim Speed: 100
Upkeep Tax: 1.2%
Strength: Strong, Slow
Weakness: Numerous
Upgrade cost: 200X(# of upgrades purchased+1)

This is your most expensive weapon in your arsenal but its well worth the cost. The fact that it can rewind a creeps advance is huge even though it can only do it once per creep. I recommend building this after where your defenses are strongest and be ready to deal with boss creeps because if you need this thing to delay them, then you need more firepower after it as well. I also recommend reducing its duration first than maxing out its distance.

Quantum Farm

Increases Pow recharge rates and awards Creds at the end of every wave. Farms are best built early to maximize return. Farms explode violently if destroyed, punishing you for you greed and hubris.

Cost: 350
Health: 250
Cred per wave: 20/30/40/50/75/100/150/275
Pow Charge rate: 1%/5%/10%/25%/50%/100%
Upkeep tax: 2%
Structure Limit: 10
Upgrade cost: 160X(# of upgrades purchased+1)

The Farm is the kind of purchase you make early on or not at all. If you do buy one, either upgrade its Cred generation or Pow charge rate, not both. Its cheaper to get two Farms and have them specialize. They do have very low health so I recommend placing them somewhere the creeps are unlikely to reach and beware the Stingers.

That's every structure you can build in the game (so far). If you have any suggestions or seen something that doesn't make sense or a mistake on my part, please let me know. Again this guide was made in hopes of sharing any useful info with other players.

Thanks for reading and I hope it helps you.