That is so cool that you like my game so much! No I haven't played Aunt Flora's Mansion, but I'll check it out. Sokoban and Jonathan Blow were huge inspirations, glad someone picked up on that.
I didn't include the option to restart the room because I was focusing more on the whole thing being one big puzzle, but a save block is a genius idea, that would solve a lot of problems! The undo feature worked based on variables of past x and y coordinates for the boxes and player, and so I had to make a new variable for every move, hence the limit, and the variables were assigned to specific instances, so they wouldn't save between rooms. However, if I end up expanding on this game or making something similar to it, I'm sure I could find a way to fix this.
The "press Z to undo" works less on AI figuring out whether the puzzle is solvable, and more on how I designed the individual puzzles and knew how they worked. For example, in the first two rooms the only way to get stuck is by pushing the blocks all the way to the top or bottom of the room, and so in those two rooms I made the game check if the boxes were touching a wall above or below them.
Thanks a ton for your amazing feedback!