The chargable spirit flinging mechanic is really enjoyable! I bet you could get some way into the game by just flinging yourself through the level, but I didn't try.
What I did try was possessing a scientist, walking into a pit, then flinging my spirit out at the last second before reaching the incinerator.... and that was hilarious!
I didn't get far into the story, but the writing was good and the notes were amyusing! Great stuff.