I love the concept here. It's like a singleplayer version of those co-op "work together to control [insert thing here] games. The pixel art and water effects are also gorgeous.
Unfortunately the passages were always a little too tight. I always ended up running into them and being unable to get out since the turning circle was so wide and every touch cleaved tons of health from the ship. I'd definitely suggest some sort of knockback whenever you take damage.
The game also felt a little slow since there was just one rat manning the ship. I guess that's why that genre of game is always multiplayer.
Still, the game was still very fun, just needs a bit of polish and it'd be even better.