Why is it called Dig Dug if he isn't digging?

The gimmick is neat but the game doesn't give you enough time before the mobs enter rush mode to properly set anything up, so the real best tactic is move n pump at the same time. Difficulty is all over the place, sometimes they're Fuck You Squares with 10 enemies while the drill areas are on the other side, others after it will be long hallways where you can easily pump enemies. Also no continues good lord who rushed this out the door?