Very fun to play with a lovely aesthetic! I do wish the gameplay was a bit more varied. I liked the idea of the flashlight upgrade, but it never seemed to get much darker. I only reached a depth of 1139m, and I see from your other comments that a little bit deeper there is some more content. I only wish the variety scaled up a bit faster.
Over all I really liked the game though! The sub controls felt very intuitive, and were just difficult enough to make navigating the depths an engaging challenge. Lots of fun!