Aliens come down and shoot them before they get to you. That may be it in a nutshell, but really this was a hugely influential game. Yeah, yeah Pong came first and drunk people plunked quarters in it. However for me this was the big daddy that really turned video games around, made them fun and made a bunch of kids want to play it over and over. It spawned sequels as well as being highly influential on tons of other popular games including Galaxian (a classic in it’s own right). The 1970’s may have started being all about pinball, but due to this game and others that came out in the next couple of years the decade ended with video games pushing themselves into arcades in a big way. The game is simple, but I think it’s still a solid game in it’s own way and it really shaped the popularity of arcade games.