MusicThe background music is in fact the catchy Popcorn by Gershon Kingsley from 1972. The other song featured, when you "power up", is the famous 4th movement from The William Tell Overture, otherwise known as The Lone Ranger Song. The familiar ditty when you die is in fact an old Catholic hymn entitled Pray for the Dead.
ReceptionDigger is the most widely recognized (and popular) of all Windmill Software titles; many patches, utilities, and even a complete disassembly and rewrite have been made. This may be due to the fact that Digger has a more complex structure than Windmill's other games which were merely variants of simpler concepts (Joust, Centipede, Galaxian, etc.).
Information also contributed by Apogee IV and WizardX