Incredible game, seriously. If you made this in a week, then I'd say expand on it for a month or two for a two or three hour game then release it on Steam, it's an absolute hit. Lots of difficulty spikes but they felt fair. Only bug I found was the end screen looped, so as it panned down it then looped back to the beginning of the scene with the boat, and so on, but not marking it lower based on that! 5 stars all round.
Viewing post in In The Depths jam comments
Boss level at the end of sections could definitely work, could also maybe spread out the mechanics? Or indeed add more a la Celeste, there's potential for loads.
With the bug, I just remember going to the surface of the ocean, seeing the ship, and then it panning down, after maybe 5 seconds it started looping, so camera back up to the first shot of the boat, then back down and so on. No further issues