Wow, I love the visual style here! The style is minimal and clean, and really helps with "reading" the puzzle layout. The alt-key highlighting is very nice, and I love having an infinite rewind to go back to the exact step I want to retry. I wasn't able to find a restart key - is there a way to jump back to the start without rewinding through all your moves? Congrats on the excellent presentation and implementing some mind-bending puzzles!