really weird bug (in makecode, not your project; filed it here: https://github.com/microsoft/pxt-arcade/issues/1844).
Somehow one of the blocks in the program got messed up, and it broke the whole thing. https://makecode.com/_g1XLrkT80PUd should work (there were a few unused blocks floating around at the bottom that I removed that ‘fixed’ it). I also fixed the missing block @Blobiy mentioned (also thanks for helping by the way @Blobiy ! I was too busy playing animal crossing all day to check till now 
) and added a few walls to make sure things seemed to be working.
Love the art by the way, Alfie is adorable. @darzu ^^ game based off your videos