Simon's bright four colour layout made it stand out in toyshops and it was a big seller. The game itself was fairly simple. You had to follow a sequence of colour combinations selected by the game's computer. There were four skill levels, thus giving it the addictive quality of all computer games: the challenge to rise to the next level.
Simon was soon joined by a pocket version, Pocket Simon and a multi player version, Super Simon. The pocket version was also known as Mini Senso and Pocket Senso.