Thanks, it means a lot to hear that it felt smooth and fun!
Regarding the Shift thing, it's not just you, I actually just messed up when assigning the notes to the rooms because there was supposed to be a note explaining that mechanic but it doesn't show up 😭 I've fixed it now, along with a couple other bugs, but I want to finish testing those changes before I patch the game (and don't want to fix too much before judging is over, in spirit of the jam and all).
The level you got stuck on is a really tricky one!! My love for cryptic puzzles kind of took over me like the green goblin mask while designing that one - the key to it is actually not to do with the mirror tool bit (that was just a gag about me copy-paste and mirroring the drawing of the lemming on the laptop) but actually the "slashing stick of forward" (or better put, "forward slash-ing stick" lol). Also the lemmings just write "lemon" in place of "lemmings" because they are silly little creatures.
It's always good to hear feedback and see what parts confuse people tho!! It's tricky finding a balance of "puzzle that makes you think, but gets solved" inbetween "extremely obvious solution" and "this literally makes no sense so I give up" 😅