Though never advertised outside of a brief mention in an old Atari marketing tape, Mark of the Mole for the Atari 2600 could have been one of the first music-based video games (if not the first), had it been finished and released.

Developed sometime between 1982 and 1984, the game was based on the Residents' experimental album of the same name, and at least two prototypes were made, an early copy that was given to the band, and a later 75% complete version that former Atari designer Greg Easter lost after he left the company.

Easter explains the game:

"First a line of music plays (one of the songs from the Residents' Mark of the Mole record) - you are a mole with a hammer who travels down into a cave and taps on walls with a hammer. Different parts of the cave make different musical notes, and when you find the next note you need to complete the line of music which was just played.

You are building a song note by note, and you have to remember the tone of the next note you need in order to get it right. Each time you play the caves are different, so you can't just remember where to go. The game actually teaches you what is called 'perfect pitch' in music - the ability to hear notes and know where they are on the staff."

While the game is now lost and perhaps never to be found again, Easter sold off a collection of materials from Mark of the Mole late last year, including sheet music written by the Residents, three polaroids of the game, and a page of programming notes that described how to convert code into musical notes on the Atari 2600.