As I went through the new Steam releases today ( a la "hey look what the cat dragged in") I came across this game. Contrary to the self-ironical name of the developer "Abyssmal Games" Abyss of Neptune is surprisingly good. As far as I can say Unreal 4 engine is used and if you like Narcosis or Soma this game might be right up your Alley.
I jumped in the game to check it out. Besides the controls a little bit too floaty (no pun intended) it is really cool to explore the Bermuda triangle.
Words of the developers:
Mature Content Description
The developers describe the content like this:
Depictions of gore, references to gore, mutilated creatures
Version 0.9.0.0. is free to download right now.
It may be wise to add the game to your library as long as it's free.
Disclaimer: I have no affiliation with the developers and/or publishers. I just wanted for this game to get some momentum as I really enjoy it and you all might too.