By default the game was played between two human players, but it was possible to modify the game so that one player could play against the computer by typing "POKE 2065,1" to type the number 1 into the memory address that controlled the number of players. The authors referred to this as an optional practice mode or warm up mode and warned that the computer opponent was not very challenging. The game was inspired by "Pong" (actually, the two-paddle "Hockey" variant of "Pong") and programmed by Rhett Anderson.