Two keys are all you need to steer the snake around the 10 mazes in this game. And, at times, two keys don't seem to give enough control. Plus signs represent the nuts you must eat to gather points, and inverse plus signs are berries to gather when ripe, but which only stay ripe for a tantalising short time. Poison balls are your enemy; if you eat them you die, you also die if you eat yourself.
Impossible, I hear you cry. Don't you believe it. The game is so fast and furious you can easily bump into yourself or any of the maze boundaries.
This is one of the few snake games in which the snake moves faster, the longer it gets. Imaginative use of the very limited graphics capabilities of the ZX81 make for a very enjoyable and exciting game. Although at first it might seem easy, it is deceptively difficult to master. Getting your name at the top of the hall of fame requires a lot of effort.