Borderline is an overhead arcade shooter that puts the player in control of a Jeep in a war zone. The Jeep is equipped with a gun that has unlimited ammunition. Each round consists of four stages, after the player has completed all of them, the game proceeds to the next round, with increased difficulty.

The first stage is a vertically scrolling shooter: the player can move the Jeep in all directions, shooting at enemies that try to destroy it by collision, the goal is simply to survive. The other stages share a different gameplay concept: the player has to navigate the Jeep towards enemy refineries and destroy them all. Enemy tanks will spawn indefinitely, trying to stop the Jeep. Parts of the stage are covered by bushes, and the Jeep has to furrow through them before advancing. In the third stage rockets can be picked up for bonus score. In the fourth and final stage the sole refinery is well-protected and shoots missiles at the Jeep.