Cool game! I really like the art, and the concept of the whole thing being a dream, and trying not to go above a certain heart rate is really cool! I also quite like the mechanics, although I do have a few pointers. The platforming feels quite sloppy right now, since it takes so long for your character to turn around/get up to speed. A bit more acceleration on the movement would be nice. Also, in my opinion, it takes too long to drown. Whenever I intend on drowning, it's quite annoying to have to wait so long. Although the screen effect is really cool! Anyway, despite those issues, this is still a really solid submission. Good job! :)
Also, maybe you could check out my game? :)