Difficulty: 3/5

Description: You're not allowed to build any vehicles or bases.

Somewhat of a boring challenge because of how tedious it is. However, it is still faster than your typical normal run. You can do it with a minimum of 2 High Capacity Oxygen Tanks.

Using the habitat builder for external growbeds is fine.

To make the run less tedious, you can tweak the rules to allow yourself to build a single 1-corridor base each on Delta Island and Glacial Island for storage and fabrication only. The Modification Station is not allowed.


Difficulty: 4/5

Description: This is a modified No-Vehicle + No-Base challenge.

This one's also tedious, but quite fun. It's more difficult than the standard no-vehicle + no-base challenge. And more challenging == more rewarding.



Main restrictions:

• When you're underwater, you must stay Below 0 meters. You're not allowed to surface for air (except at any of the mandatory story "islands" listed below) or use any bases/vehicles.
  
• When you're on an "island", you must stay Below 0 degrees (not literally) in the sense that you can't wear a cold suit or use any bases/vehicles.

You're only allowed to surface on the mandatory story "islands": the initial crash landing location, Delta Island, Glacial Basin, the Greenhouse iceberg, the Outpost Zero entrance, the final Architect Gate area.

Other restrictions:

• No vehicles allowed
  
• For convenience so you don't have to keep backtracking to your original drop pod, you are allowed to build two 1-corridor bases for fabrication and storage only. 1 can be built anywhere on Delta Island, and 1 can be built on Glacial Basin next to Phi Robotics Lab.
  
• Growing plants at your 2 bases is allowed
  
• You are allowed to have a maximum of 3 High Capacity O2 Tanks for this challenge. Almost all of the challenge can be done with just 2.

The first five minutes will be tight. You start with 45s of oxygen, and it takes a little longer than 45s round trip to get the nearest creepvine seeds from the drop pod. Basically, you can barely make it before completely blacking out.

Conditions for clearing:

• Beat the game
  
• Bonus objective 1: Visit Maida at her greenhouse. I completely underestimated how hard it would be to find her island while staying underwater.
  
• Bonus objective 2: Visit all Architect Artifacts (you will definitely need 3 HCOTs for this)

I've cleared the challenge myself, so I know it's doable (without resorting to glitches, air pipes, eating bladderfish for air, etc.).

Difficulty: ~ 1/5

Description: You know what to do, you monster. Kill at least 1 of every animal. The method does not matter.



Hit List:

• Smaller creatures: Brute Shark, Cryptosuchus, Crashfish, Pengling (did I stutter?), Snow Stalker, Sea Monkey
  
• Larger creatures: Chelicerate, Void Chelicerate, Shadow Leviathan

Personally, I don't like this challenge, but it's a commonly-requested one.


Difficulty: ~ 1.5/5

Description: You're not allowed to use or hurt any fauna (creatures). The challenge run ends after you've built an interior growbed and water filtration machine.

It's slightly harder than a vegan run in the original since you can't use coral + salt to make water.


Difficulty: ~ 2/5

Description: Nothing special. Simply beat the game in hardcore mode. It's easier if you complete this faster because there are plenty of bugs in the game that will gladly end your run.


Difficulty: ~ 1.5/5

Description: Complete the run without building any bases.

This one's for Sea Truck lovers with a lot of patience.


Difficulty: ~ 2/5

Description: Complete the run without any vehicles.

This one's for Sea Truck haters with a lot of patience.