I liked the art. It's very simplistic in a good way. I also quite liked the somber music, it was somewhat fitting. Doing a 3D game for a short jam is always very impressive, too.
I do wish more was done with the fish being a mechanic though. I also felt like the jump was too powerful, since I skipped a few segments by accident. Maybe replace the timer with charge bar?
I didn't finish it, but that was mostly out of boredom. The opening section where it's impossible to fall back down dragged on too long. That plus the jump cooldown timer made the need to go back up more tedious than infuriating. Maybe that's jut me not being able to get mad at games that intentionally label themselves as rage-inducing or hard?
Overall, it's a good game. Just needs some polish on the mechanics.