Berzerk is a multidirectional shooter designed by Alan McNeil and released for arcades in 1980 by Stern Electronics of Chicago. Following Taito's Stratovox, it is one of the first arcade video games with speech synthesis. Berzerk places the player in a series of top-down, maze-like rooms containing armed robots. Home ports were published for the Atari 2600, Atari 5200, and Vectrex.
A sequel, Frenzy, was released in 1982.
When the game begins, the player controls a green stick man on the left of the screen. In two-player games, the second player controls a purple stick man on the right of the screen. Each player plays until they lose a life, allowing the other player to have a turn.
Using a joystick and a firing button that activates a laser-style weapon, the player navigates a simple maze filled with many robots, who fire lasers back at the player character. A player can be killed by being shot, by running into a robot or an exploding robot, getting electrocuted by the electrified walls of the maze itself, or by being touched by the player's nemesis, Evil Otto.
The function of Evil Otto, represented by a bouncing smiley face, is to quicken the pace of the game. Otto is unusual, with regard to games of the period, in that he's indestructible. Otto can go through walls with impunity and hunts the player character. If robots remain in the maze Otto moves slowly, about half as fast as the humanoid, but he speeds up to match the humanoid's speed once all the robots are killed. Evil Otto moves at exactly the same speed as the player going left and right but he can move faster than the player going up and down; thus, no matter how close Otto is, the player can escape as long as they can avoid moving straight up or down.
The player advances by escaping from the maze through an opening in the far wall. Each robot destroyed is worth 50 points. If all the robots in the current maze have been destroyed before the player escapes, the player gains ten points per robot.