Viewed from a top-down perspective, each player controls a "snake" with a fixed starting position. The "head" of the snake continually moves forward, unable to stop, growing ever longer. It must be steered left, right, up, and down to avoid hitting walls and the body of either snake.

The first known personal computer version of Snake, titled Worm, was programmed in 1978 by P. Trefonas from the USA on the TRS-80 computer, and published by CLOAD magazine in the same year. This was followed shortly afterwards with versions from the same author for the Commodore PET and Apple II computers.