Things I liked:
Movement:
Movement felt very good, gliding across the floor and bouncing around was very fun.
Level design:
The subtle design of the levels was very cool.
Level editor:
A very unexpected feature, but impressive, nonetheless.
In-game tutorial:
Always nice to have one.
Things I disliked:
The difficulty:
The difficulty seemed way too high. The only way I found to defeat the shadow was to run with the fireball, and I couldn't defeat the jetpack guy.
Synopsis:
A very interesting game with really neat movement, but with serious difficulty.
Thanks for your entry. :)