I love the "systems" aspect of the game, really creative and great potential. When you got the hang of the different systems it was awesome to play piano and switching all systems on and off. I the idea of systems simulators for this reason and this had the perfect number of systems and interactions. Cool graphics as well!
I only had some problems that are not related to the actual gameplay, so bear with me:
1. I did not understand the progression of the game, or why I would move around and risk dying instead of just staying still and repairing and then I had no indication that the repairs actually was doing anything. Maybe some objectives like finding missing parts or survivors or something else in the deep would make the objective more logical.
2. I had no reason to go "Deeper" and no reason to not go to the surface to not drown (makes sense to go upwards if the sub is broken). Depth 0 was not on the surface :P
3. What does having your systems at -1 mean? Did not make much sense to me, would it not make more sense to just up all the scales by one?
4. ";" did not work as a hotkey for me, I don't know if it has anything to do with my nordic/german keyboard layout.
5. Missing some sounds
The gameplay was really awesome though. Really enjoyed this one, good job!