I'm stuck after getting the pulse. Saw a giant sea snake, but can't open the door. A few high spots I don't have the height for,, a few water ways I don't have the breath for. Not sure what scanning the vents does.
Thoughts so far. I'm enjoying it quite a bit. Great atmosphere; I like how the music muffles when underwater. And the platforming and laser/breath retention puzzles are good, if a little fiddly to pull off. There's some weird respawning bugs here and there, but they're hard to articulate. (Maybe be clearer in the videos.)
Climbing out of the water was a little fiddley to work out. You have to hold up and right/left but you need to be slightly below water for it to work. Spent quite a bit of time in the first room trying to figure that one out.
It took me a while to figure out what scanning does, and conversely how to use the med-kit. You should either put a medkit in the first room, so you have something to scan right away, or move the scan prompt to the room with the medkit.
I'll upload my videos, but I'll try to finish the game if you can point me in the right direction.