It was a pretty good platformer base, you do need to work on the jumping a bit. It's strangely weighty and I missed a bunch of jumps because it felt sped up. You also need to add some feedback to the player so they know that they are progressing, I only killed the final boss because there was nothing else to shoot at but right up until he vanished I didn't know if I was doing the right thing.
Otherwise it's really good, the level layout is great and the general fx are nice.