Fun little game! I enjoy that hitting a spike isn't a hard fail for the game and the player can enter a ghost mode. That was awesome. I also like how the mouse revealed different parts of the world like spikes and hidden areas.
If you wanted to improve, I suggest adding some sort of penalty for going into the ghost mode. When I played through it I didn't care if I was in ghost mode and just stayed as a ghost for most of it.
Overall, fun game. Please check out mine if you get a chance!