This is vastly underrated.
I have to admit, I spent a whole hour on this. You've created a beautiful world, in spite of the crudely drawn characters. It was puzzling, and a real sense of accomplisment when they were solved just made the game that one step greater.
The music is fabulous, and the achievements themselves were both simple and challenging to obtain.
However, what keeps it from a 10 is the horrendously slippery controls. I found it difficult to keep still half the time, always falling off mini platforms - it was too much. Coupled with that were a couple of instances of bad collision detection where i would fall through platforms without Ghost - these were, thankfully, few and far between.
Overall, a magnificent game. Well done.