Heater/Coolant suits should need fuel.

Coal for warmth generation and something radioactive for coolant systems.

Perhaps scaling with difficulty level. From you don't need fuel, to you need a consistent amount of fuel, to you need more fuel depending on how cold/warm the area is which gets more demanding as you go deeper.

Every suit should also have an output percentage. Wherein 50% makes it so that you don't get any warmer(or colder), 70% gets you into a more positive status while costing more fuel, 100% even more so, 30% saves some fuel but makes it so that you still get colder and will need to build some fires along the way, and 0% kills you because what are you even.




For.... Reasons.

 

I agree,
The scuba suit should have oxygen tank. Top tier suit has re-breather
Heat suit requires coolant, top tier has heat shielding
Toxic suit needs to be repaired as it degrades- top tier is ?
Space suit is same as scuba but also has power consumption for heater.

 

And most importantly either remove the unlimited oxygen from the heat and cold suit or give the oxygen nanosuit another bonus so you don't feel cheated when it's useless 10 minutes after you got it >.>

 

There are actually scuba tanks in the game, stackable unlike most worn items. Haven't tested whether they're functional or not, but i found them in a chest at the bottom of the ocean...

 

They used to be functional, but they removed it.