The sprites are cute! And I really like it when those big skull heads drop on the floor, make a big thud, and the camera shakes-- the game feel from that is very nice. And I liked that sequence where you had to just keep running and jumping to avoid the slew of falling skulls and jack-o-lanterns; finishing that all in one go felt really good. The music is nice too.
I had issues with the i-frames and collisions though; sometimes I would get hit by an incoming ghost worm enemy and it would knock me back and then hit me again as I was being knocked back and recovering.
Nonetheless, I enjoyed playing! (And yikes, that ending was spooky!)