Neat. It took a couple of tries to see exactly what I was supposed to do, but once I understand the plot of the system it was simple enough.
I topped out at Year 8, myself; I just couldn't get my snake any longer than that.
Main suggestions for improvement would be:
1. Maybe a line or two to stipulate what the goal is. Someone less wiling to try stuff might not realize: Oh, I have to eat the red and yellow snake butt.
2. Maybe make whichever part you are flash a bit, at least the start of a cycle, especially for those who are colorblind so they can know what snake they're controlling. I'm not colorblind, myself, and I kept getting confused at the start of a round as to which snake I was controlling; so I can just imagine the horror a CB person would suffer.
But overall, a neat little game.