Great to see a platformer! Very promising art too. A couple things I think could be improved on this one are some of the character control/movement things though. The lack of I-frames is a big one. If you take damage, you will continue to take damage every frame. This is compounded by some jumps seemingly being impossible without taking damage.
Another pain point was the attack. It seems to default to attacking to the right, even if the character is facing left. Only if the character is moving left will it attack left. An upward/jump attack would also be nice, seeing how most enemies are flying.
But, overall, the art style was very charming & a gamemaker platformer in the Jam was a breath of fresh air. Great for a first game!