I found a repository with Nibbler in it and gave it a few goes. Super hard, and I noticed two things. In attract mode it says 'does not stop at corners'. It does, but the time varies according to the directions available. From one of the corners it's probably four times as long as if every cardinal direction is available. Then it cascades depending on the open-ness of the layout. Next, the speed of activation of input is FAST. Note the speed of character change when setting initials. It's like an analog control set really high. In essence, the game seems loaded.