Very interesting and thought-provoking entry; I liked that you were able to create a game based on your own experience with hypnagogia, and the story of the game was really nicely told. Based on the memories you collect, I could piece together what happened and it's definitely a sad tale; wasn't expecting to see a game with a deeper story in a game jam, but this is really great! Bonus points for having voice acting too :)
On the game/gameplay side, what initially confused me was the climbing and diving mechanic; a minor nitpick, but I would've preferred diving to be on E instead of R, as that way, the climb and dive buttons are right next to W. I got confused for a bit cause my muscle memory kept pressing E to dive.
Also, I think the mechanics are interesting but can be hard to understand because there's so many different parts to the game: you have phase shifting, the awareness meter, the nightmares, and how deep you've gone that affects the awareness meter gain rate, so it's a bit overwhelming, even with the 2 pages of help. Maybe one idea if you explore this game further is to break up the memories into different stages that slowly introduce the mechanics to the player, so it's easier to digest.
My only other nitpick is that the movement is a bit slow. But overall, I enjoyed this game and liked the angle you took with the theme; excellent job on the submission!