Hi! Great job on this submission, it looks pretty good!
I have a few bits of critique, the first being that your game currently sways a little bit. I'm not sure if this is on purpose, but the camera doesn't quite follow right, and it's difficult to see where the sub will end up. I really like the jellyfish, and the sharks are very cool, I also think the damage amounts per enemy is good. Next bit of critique is just that currently, when in fullscreen mode, some of the elements are difficult if not impossible to see when I played.
Other than this critique, your submission fit the theme very well, good job!