Set in an alternate version of our modern world, Over G Fighters has players join the Energy Air Force to defend countries against terrorist threats all over the globe. You command one of the many available jet fighters, ranging from F-22A Raptor to MiG-29A Fulcrum and even stealth fighters. In the main scenario mode, you select one of the missions in the world to defend or take out targets, or destroy enemies, with primary and secondary objectives. After an introduction outlining the scenario, you take off with a limited amount of ammo, and sometimes wingmen who can be commanded to support your strategies.

You will be attacked in the air and from the ground, and planes have a realistic damage model where specific parts such as the engine or the wings can be damaged. Completing tasks advances the story and unlocks new planes. After each mission, you are graded based on your performance. Your actions can be stored on the flight data recorder and replayed afterwards.

In the Challenge mode, you can design your own scenarios to test tactics and fly specific planes. The online multiplayer mode supports up to eight players in both co-operative and head-to-head missions. You gain ranks for making kills.