One of the best games I played in this jam so far! Love it. Visuals are 5*. Everything feels in the same art style and color scheme, that so important and you nailed it.
As a fan of Subnautica I liked the theme. Gameplay was addictive and enjoful. I like how it's one big "world"instead of levels and the deeper regions are like new levels with new enemies. The enemies like Jellyfish or sharks had no sound design sadly. A buzzing sound or a "warm up" sound for the jellyfish can help the player to time the movements better. I like the music, very calming and fitting for the underwater world. The piano pice in the menu feels like a diffrent world and doesn't match the sound world of the level music. I see one of the tracks is coming from Pixabay.
If you like to work further on the game and want an individual composed soundtrack I can help. I'm a video game composer. You can check out some of my work in our Jam entry if you like.