the boss fight was somewhat interesting, but other than that I can't really say much about this. The character walks slow and can only jump, and if you die you have to go back to the beginning of the level, which doesn't take that long but because of the player's speed it feels like a slog. And the limitation doesn't impact the gameplay at all.
I don't want to be completely negative, so I'll just say that if you want to improve for next time you should A. Respect the Player's time (Don't make anything overly slow and don't make them repeat too much of a segment they've already done) and B. Some kind of unique idea behind the game makes even a not too great game at least more interesting than a normal platformer with nothing that different.
I'm sorry about being so negative but I do hope you keep doing game jams, they're pretty fun and stuff!