Top Gun is a combat flight simulation game. The game is viewed with two vertical split screens, one for the player's fighter plane and one for an enemy plane. Both screens are viewed from within the cockpit. On each level, the player faces off against three enemy planes, one at a time. The player advances to the next level after defeating the three planes. The player can use a machine gun and missiles against enemies, who become more difficult to defeat as the game progresses. The machine gun is prone to overheating if used continually, and missiles must be locked on to a target for three seconds before they can be launched. Enemy planes also have missiles, and a single missile is fatal to both the player and the enemy plane. The player can drop a flare to distract an incoming enemy missile. An instrument panel gives the player information such as altitude, speed, and machine gun temperature.

Top Gun includes a two-player mode in which both players receive three planes. Both players start with a plane each and use it in combat against the other player. If a plane is destroyed, the player uses another one. A player loses the game if all three planes are destroyed by the other player.