This first entrance in the timeline is a short audio clip is from the arcade game DigDug, which was released in 1982. This song specifically was created in Japan by composer Yuriko Keino, who was initially tasked with creating a walking sound for the playable character of the game. After struggling to create a realistic sound, Keino created this very short melody that plays whenever the player moves. (2)
This being one of the very first games to contain continuous music, this audio track is extremely short and simple in nature. In fact, only two 'voices' are used in this song -- both of which are simply plain 'pulse-waves'. One is for the basic melody of the tune, and then another underscores the piece. As is obvious to anyone listening, this does not resemble any traditional music that one might hear, with no recognizable instruments being implemented.
This sheet music makes more clear how simple the composition is. There are only two different parts to the song, as the sound chip technology at the time was only able to accommodate two channels.