Cool game with some nice enemy variety.
I really like the sprite designs, the player sub is cool with its free aim turret arms, and the glowing fish enemies are really a nice stylisation to convey that you are in very deep waters with its strange sealife.
Music is really good as well and fits perfectly with the game's vibe.
Main issue for me is the base gun feels really slow (rate of fire) and there were no powerups to get a better one, it would be nice to either have some or to buff the base gun a little if you prefer having only one weapon.
Other than that it's good, it's fun, and while the difficulty ramps up quite a bit throughout stage 2 i liked that it wasn't just pure insanity from the start of stage 1
Well done :)