Subnautica!
 

Subnautica is a game where you must survive on a hostile alien planet until help arrives. Made by Unknown Worlds (The blokes behind natural selection 2) This game is still in early access and is soon to be complete.
http://store.steampowered.com/app/264710/
What are your thoughts? I find it to be fun.

kind of off topic but natural selection was soooo good ~13 years ago