There's a lot here that impressed me - character animation, the jump dust effect, a bit of screen shake juice. That attention to those extra touches that improve the game feel means you're on the right path. Having one or two extra animations for the enemies - an attack and a death - would have been great as well.
I think the main thing that could have improved this would be some kind of checkpoint system, as it was quite disheartening to start again at the beginning of the tutorial level. Some sound and music also would have gone a long way, but I assume you just ran out of time in the end.
Congrats on your first jam! You should be proud for making it :)