The game's playing field consists of a matrix of 11 buttons; each button contains a red LED . These buttons can light up or blink. The array is encased in a red plastic case, which bears a slight resemblance to an overgrown keypad . Four game selection and control buttons are also located on the bottom of the device; a speaker occupies the top portion. Supporting electronics (including a simple microprocessor ) are located in the shell of the game. Parker Brothers later released Master Merlin with more games, and the rarer Split Second , where all the games involved time with a more advanced display, with line segments around the dots. Both had the same general shape and came out a few years after Merlin.

Merlin's simple array of buttons and lights supported playing six different games, some of which could be played against the computer or against another person.