Its an interesting idea, i loved the swimming animations. I think its a pretty cool concept that I would be curious to see explored more, but in the current state, I found the difficulty to be not from any kind of puzzle or fun mechanical challenge, but just the tediousness of balancing moving quickly and making sure the characters dont drift too far.
I think maybe making the objects have a little less floatyness when theyre near the "correct" spot could help make it easier mechanically.
And maybe I just didn't get far enough, but adding in more constraints into the level to make it into more of a puzzle game where the solution isn't super obvious would help. Puzzle design is hard tho and we didn't have a lot of time, so considering that, overall, was very enjoyable.