Nuclear Throne

This isn't really an achievement where a guide can be written that will tell you how to unlock it since it is ultimately skill based. There are however strategies and mutations to consider that may help you along the way. I will do my best to add tips here that I came up with that helped me to finally unlock this though be warned it took me approximately 12-18 hours of game time to actually unlock this.


Take things slow and keep your distance from enemies. The run where I finally got the achievement took between 30-40 minutes because I took my time and was very patient. This is key to not taking any unnecessary risks/deaths.

Mutations:
The most crucial part is to make sure not to accidentally pick the rhino skin or strong spirit mutations as these will void this as per the achievement text. The most important mutation in this challenge in my opinion is ***scarier face***. This mutation will make the boss fights more manageable and allow you to kill enemies before they can kill you.

*****Pick Scarier Face over anything else as it is a game changer!*****

Other helpful recommended mutations in no particular order are:

Euphoria (Slow bullets): Extra helpful against the throne and in my opinion is very important to winning this fight.

Back Muscle (Higher Ammo Max): Helpful since with the low health total it is advisable to stay far away from enemies, which may make you run low on ammo. This helps to prevent this.

Boiling Veins (No dying from explosions): Makes you be able to use explosive weapons if you wish without worries and helpful against the explosive enemies in world 6.

Bolt Marrow (Crossbow Aimbot): This is a very useful mutation that makes the crossbow very powerful.

Gamma Guts: This will prevent deaths to the enemies on world 6 and rats, potentially others. This may save you in a pinch but otherwise isn't all that useful with 2 health.

Plutonium Hunger (Suck in everything): Very useful since you'll be keeping your distance from most enemies.

Rabbit Paw: More ammo drops.

Shotgun Shoulders: My favorite weapons are shotguns with shotguns shoulders for this challenge since you can bounce the bullets around corners. This is a very good way to kill enemies without any risk of death since they cannot shoot you. I recommend considering this as well since if by pure chance you get the wave gun, everything will be a lot easier in the later stages. Getting it early will also help in world 2/3 since there are a lot of thin passages.

Throne Butt: Makes your left trigger ability much more impactful and dangerous to enemies. Good but I usually put priority on others.


Weapons:

I like to have a combination of a power weapon for bosses and a lighter weapon for room clearing. My personal favorite combinations are either Explosive/Shotgun, Crossbow/Shotgun, or Crossbow/Explosive. I would only prioritize the shotgun if you have shotgun shoulders early on since it makes the game easy in the beginning 3 worlds. There will be some drop off, but hopefully you can find a flame shotgun/auto flame shotgun/ double flame shotgun since these deal very high damage and stun enemies which is very useful. The stun makes it so enemies cannot shoot at you and push them from you. This is a great way to keep distance. For example if you shoot the flame shotgun at an approaching jumping dog enemy (The very dangerous green blob that jumps at you) in world 7 and you shoot at it with the flame shotgun it will stop the jump animation and push it away.

Crossbows and Explosives are great boss clear weapons especially with scarier face. You will be able to kill most bosses with less shots and relatively quickly, lowering your chances of death. Below I will list my strategies for each boss that may help you get better at consistently killing them without damage! Heavy crossbow is very good as it kills bosses quickly late on with scarier face. Explosive weapon options are Rocket Launchers/Grenade shotguns/Grenade Rifles but only if you have boiling veins to prevent tragedy of killing yourself. The auto rocket launcher is very good at killing the throne at the end if you just spam it so that is something to keep an eye out for.

1-3 Bandit Boss:
On this stage I will move slightly towards enemies and kill a few but then run back to where I spawned and wait for the boss to spawn. This will create separation and let you kill him before any other enemies can shoot at you. You can kill him with like 3-4 grenade launcher shots/ 5 crossbow shots. Less if you have scarier face very early. You will need to be able to get through this world without taking damage consistently before time as it is the easiest of the areas.


3-3 Big Dog:
This is one of the luck based spawn rooms that will make or break most runs. You will either spawn in a wide open room where it will be very difficult to live since there are usually very many annoying snipers that spawn behind the Dog. If you are in a wide open room I would prioritize killing the snipers as they will constantly fire at you and any of the shots will kill you. From there dog is relatively easy to dodge and kill by just firing crossbow bolts or grenades/rockets at him.

5-3 Jetpack Boy:
This is the most annoying boss that is actually very simple to kill if you go about it the right way. When you spawn, if there are no other enemies near you just wait until you hear him make a sound. He will drop right on your spot where you're standing and you should move away as soon as you hear it. Aim at where you were standing with the heavy crossbow or other boss weapon. Shoot him as soon as he lands and go to cover and shoot again. If you're lucky he will be dead before he even has a chance to jump again and will explode away from you. From here you can just carefully clear the rest of the floor!

Nuclear Throne:
This is by far the most stressful boss in this challenge and I don't really have the greatest tips for this. Euphoria will make dodging him easier and if you stand on the red carpet and listen for the screeching sound you can then step off and bait his laser attack. The best part about the laser attack is it can't shoot the other attacks while doing it giving you time to deal free damage. You should shoot him with everything you got and after he dies and you sit on the throne you will be done!


The only other tip I have is to make sure you use your left trigger ability! It will cause explosions on the bodies off all dead enemies and clear off bullets from the screen. This can save you and kill enemies that would be tricky to kill otherwise so don't forget to make use of it.


Extra optional tip:
If you have an explosive weapon on world 2 you can go to the secret ninja turtles level ***but only after clearing the rest of the floor to maximize mutation progress***. The nice thing about going here is that it will let you get better weapons a floor earlier as the way weapon drops are based on number of levels cleared. This secret level is purely bonus and doesn't skip anything so you can get weapons a floor early. This may be the difference between success and failure so if you have the option I'd take advantage of it.
To enter the secret world you must find a sewer grate on the floor and shoot an explosive at it. This will open the portal to the secret world.


Good luck as this is a very challenging achievement that has both skill and luck involved heavily. As a final note, what worked for me may not work for you. If you find weapons not to your liking, try experimenting and find what you like. This is very crucial to performing well in this game since there are many different ways to complete runs and there is no right answer as to how to play this game well. There are plenty of valid strategies and you can further research them online as well if you wish.