Seesaw (I forget what number and the level select didn't seem to work. I want to say 21) & Level 27 need some color coding on the buttons, but otherwise the difficulty was perfect.
Very nice "double take" puzzle design. I love being forced to recontextualize the puzzle after a red herring, although I started to distrust your initial placement after a while and figure out the trick early. Which leads me to my next point:
May I suggest an option to hide level names, since sometimes the name tipped me off to what the red herring would be?
Lastly thank goodness for the undo button.