The snake's "instincts" can be really annoying to fight against, since when you are run into a wall you it sometimes forces you to go in whichever direction has priority, even if there is room to go the other direction without overlapping yourself or turning more than 90 degrees.
The snake would be a bit less painful to deal with if it was just a bit slower and didn't ignore my input when choosing which way to turn at a wall. Sometimes I know exactly how I need to maneuver him, but getting him to actually do it feels like trying to thread a worm that keeps squirming through the eye of a needle.
That being said, I actually really like this submission. It's a creative use of the theme and it's a clever puzzle mechanic that I can get behind. Just figured I'd nitpick a bit since all of the other comments were nothing but positive. Great submission!