Heiankyo Alien was a video game created by the University of Tokyo’s Theoretical Science Group way back 1979. Originally developed as a personal computer game, it quickly grew in popularity and and was first published by Denki Onky? Corporation as an arcade game in 1980. In the game you play a keeper of the peace during an alien invasion in bygone Japan. You have a shovel and must dig holes for the aliens to fall into and then you cover them up. Sounds simple? It is, and very addicting.
Since its original release, the game has been ported to several other gaming systems, including the only version I have played, the one for the Gameboy.