Good job on completing a game for the jam! Fun, but very challenging. I was only able to beat the first two levels. Some feedback:
As DennisMagnusson mentioned, the music only plays in one ear. That can be pretty jarring for headphone users, so I recommend making sure the music is panned to the center.
Not being able to walk diagonally against walls is a little frustrating (if it's not intentional). Normally x and y movement are calculated independently.
This didn't affect me, but if you are using WASD controls, it's a good idea to let the arrow keys work as well. Some users may have different keyboard layouts that make WASD unusable.