wonderful experience! real cool idea and well put together. the pixel art people where so funny!
great job overall!
little nitpick moment:
- make sure to change Filter Mode in the sprite settings to "Point (no filter)" to prevent the pixel art from becoming blurry (as is happening with the stairs, the background and the ghost itself) it will keep the image nice and crisp ;-)
- maybe add different inhabitants with different movement speeds / patterns to add even more complexity?