This was absolutely delightful, I wish it went on for longer.
Bugs I found:
At one point I jumped into the void in level 4 and was transported to a part of level 5, where I got stuck. At some point in the "4, 5, 6" room I was glued to the floor and I had to listen to elevator music. This was solved by a reset. Sorry if this isn't clear enough, I am completely tired!