Hey man! Great game! I got pretty far and really enjoyed the experience. For being a demo, it's got quite a bit of content!
The screen shake was great, and the replayability definitely got me stuck in. I think if you have 1+ lives and time runs out, you should be able to restart from the last level you were in. The animations are solid! I love the increasing difficulty. The levels in the 2nd world felt a bit like deja vu. I was excited to get to the 3rd world but it was really hard and things stopped there.
Great work on your game! Hope it makes a full release.