Description taken from Arcade version of this game

The layout of Berzerk is quite simple. You are a human. You are trapped in a 2D world surrounded by deadly robots looking to kill you. You have a laser to destroy said robots. They have lasers to kill you. The walls can kill you. So can an evil bouncing smiley face appropriately named Evil Otto. Escape a level to advance to harder ones where robots will shoot multiple shots and move about faster. Advance very far in the game and robots will move insanely faster and so will their shots.

Fortunately, the robots must be running a relatively basic program because they are not too smart and can be fooled into killing themselves by running into walls, running into each other, or shooting each other while trying to shoot you.

Evil Otto cannot be killed, however, and is only there to discourage you from lounging on any one level too long.

The controls are an eight-directional stick and fire button, and on most machines an extra man is available to you at 5,000 points, but this is an adjustable setting.

One of the most notable characteristics of the game is its early use of voice synthesis. Classic arcade phrases such as "The human must not escape," "Intruder alert, intruder alert," and "Chicken, fight like a robot" all emitted from Berzerk. ~ Michael Schwartz/Joan Dykman, All Game Guide