This was a lot of fun! I enjoyed the focus on a simple but well-elaborated-on mechanic. Just about the right level of challenge, I think, though I was hoping for a few more levels than there were. I think I also did the last few levels in the reverse order than what was intended, since they got easier as I went. Generally, though, the difficulty curve was solid. I’m not sure how much this could be expanded without adding new mechanics, but I think the meta-puzzle angle might have room to be explored further.