Quadrun is a video game for the Atari 2600, where the objective is to destroy enemies, known as “captors,” and rescue friendly characters, called “runts,” who are trying to escape from the arena’s central building. The player character is invincible but has a limited supply of their weapon, an energy ball that destroys enemies upon contact.
The game consists of a series of waves of enemy characters. In each wave, enemies appear one at a time in the vertical section of the arena. Enemies come in various shapes and attack with different patterns, although all enemies within a single wave will be of the same type. Some captors proceed straight through the arena, while others split in half, zig-zag, or reverse direction. The player must launch the energy ball at the enemy character and then switch to the other side of the arena to catch it again. If the player does not catch the ball on the other side, it is lost.
Occasionally during a wave, a runt will attempt to escape and run through the horizontal section of the arena. The player must move into that section and touch the runt before it collides with the deadly ends of the arena. If the runt is not rescued, an energy meter at the top of the screen will shrink. The meter will also shrink if an enemy character is not destroyed during its pass through the arena. The game ends if the bar disappears or if the player loses all energy balls, either through failing to catch them or through a collision with an enemy character.
After completing five waves, the player faces a random attack wave where enemies can be of any type at any time. Before the start of the random wave, the energy meter returns to full length, and the player receives bonus points for their remaining stock of energy balls. Points are also scored for each enemy destroyed and each runt rescued.