Thanks Slowbision! Glad you like it :). If you have any ideas how to improve on the game, don't hold back ;).
I have 2 suggestions! But they are very minor.
The first is when replaying the level, seeing the intro every single time (the launch sequence) could frustrate players.
secondly, I love the way the sub maneuvers but when you reverse, it seems to instantly stop all velocity, but the same doesn't happen when you go forward, it's a little jarring.
Very small things, I loved how well polished the game felt, very original!