Your core gameplay was well-established(running, jumping, attacking), but I was expecting some kind of twist. I do like that when the Acorn dies, it resurrects in the same spot, and the animation for it is interesting.
I would have loved to see this incorporated as a mechanic in gameplay though.
I had some issues playing on my laptop due to the resolution of the game being a bit too high, also the hearts would empty in a weird order, and sometimes I don’t die even with no hearts. But honestly, I wouldn’t concern myself too much over that, since it’s a game jam, I would recommend you go back and smooth out the gameplay and remove some bugs, just for the learning experience.
Apart from that, the art is solid, and I’m a big fan of the huge-rabid looking squirrels.