Y
(Your game is the first in this video)
What a cute little spook! I rather liked it - I do wish there was just a tiny bit more of a gradual buildup, maybe a hint or two to the nature of what exactly happens, but all the same, for a quick little experience it was fun - and the music is great.
And, spoiler alert here, the menu refusing to let the game work after beating it is a nice touch.