Thanks! The last level was my favorite. I left too much of the level building for the end, and some of the early ones didn't get as much attention as I wanted. (I wrote a script to make sure they were all solvable, and that all the non-tutorial ones required at least one mechanic other than walking, but I never was able to get the script to reliably test whether you needed to interact with a guard on levels that have them.)
If we had gotten a fourth day, better level design and trickier guards were next on my list :-)