Frenzy was an arcade game published by Stern Electronics in 1982. It was a sequel to the hit 1980 arcade game Berserk.
Frenzy followed the basic paradigm set by Berserk: you are in a maze full of hostile robots who are shooting at you. The goal of the game is survive as long as possible and score points by killing robots and travelling from room to room. The game has no end other than the player losing all of his or her lives.
You have a gun, so you can shoot back, and the robots are fortunately not that bright, and can often be tricked into shooting each other. If you linger too long in a room, however, a bouncing smiley face, "Evil Otto", appears, and relentlessly chases you. Evil Otto will happily destroy any robots in his way, and can move through walls.
Source: Wikipedia, "Frenzy (video game)", available under the CC-BY-SA License.