Very nice, especially for the first jam. I was impressed and drawn in by the graphics, the sound effects and animations were spot on. The controls were OK, shooting took some time to get used to.
I didn't manage to go very far - the transitions between the rooms disoriented me, I couldn't find my way out of the first few rooms. Decided to jump into space obstructed by some bushes, just to see if I'd find a secret exit there - then I appeared in the middle of some room with spikes to the right (and a trampoline mooshroom in the middle). I could not make it neither by the closed door on the right or the wall o the left.
I would definitely spend more time on a version with bigger areas, or at least with a less eager camera, it's a great material for SMVM.