Wally is one of the 10 different songs that are played during a regular game if using the CD audio track. It is the ninth track that is played. The tracks are played in sequence starting from Cave and ending with Gray Sky, at which point the list starts over from the beginning.
A MIDI version of the song was also composed in Cakewalk that was used when the game CD wasn't in your CD drive. It was also used in the demo version of the game. In the MIDI audio track, it was used as the eighth track. These were played in sequence starting from Sick Sate Rittim and ending with Rain, at which point the list started over from the beginning.
The song title has been confirmed by Stephen Rippy.