Just wanted to chime in to say that it seems like all the puzzles are still solveable without the shift key. (I'm mid-way through the flip-flop section, perhaps

Just wanted to chime in to say that it seems like all the puzzles are still solveable without the shift key. (I'm mid-way through the flip-flop section, perhaps there's moments you need it in the final level?) edit: I take it back, foiled by delay