Really neat for what it is! There's a good idea here, and while movement in the earlygame is a bit unbearable, it doesn't take too long to get better. Trying to platform with a high jump or speed can get hard, though, and I feel like it could be more obvious when you die from lack of oxygen- it took me a bit to realize that was what was happening. Finally, it's very possible to softlock through just not upgrading jump. Not too big an issue since the game is so short though.