Okay, first of all, that is one cute ghost. I love the overall look of this game, especially paired with the music! It took me a little while to figure it out, especially with trying to input movements with WASD vs the isometric view point, but once I did it moving the character started to feel pretty natural. I was disappointed it stopped where it did! That should give you an indication on how much I was enjoying myself. I was making ghost noises as I glided around the levels.
It looks like you've got a good foundation of a game with a lot of puzzle potential. (The last level you put in was actually a pretty good one!) Nice work!
Finally, did I mention that the ghost was cute? It's very cute.