This game is really cool!
It's fun to play, the music is catchy and the graphics are simple but effective.
The theme is very well respected and it's more original than a simple scuba dive.
The game is almost perfect for a game jam except for one detail:
It's slightly too hard (I think the enemies go too fast). It would have required increasing difficulty with depth. (the deeper you are, the more enemies there are and the faster they are)