The player controls the game's silent protagonist, an ISAF pilot known by the callsign Mobius 1, while interludes are narrated by a man from San Salvacion writing a letter to Mobius 1 after the war recalling his childhood memories of wartime. Erusea gains control of most of Usea's mainland. Erusea is opposed by the Independent State Allied Forces (ISAF), but ISAF is forced to retreat outside Stonehenge's range to the island of North Point.

Stonehenge is repurposed as a long-range anti-air weapon. Erusea also captures an array of anti-asteroid railguns codenamed Stonehenge which was developed to destroy the asteroid's fragments. Just before the game starts, the Federal Republic of Erusea invades and occupies the neutral country of San Salvacion. The impact events cause over 500,000 deaths in the first two weeks as well as an international financial crisis and refugee crisis. Four years prior to the events of the game, a massive asteroid enters and breaks up in Earth's atmosphere. The game is set in the alternate universe of Strangereal where Earth has different landmasses and history. On easier settings the player can survive several missile hits, while on the hardest a single missile can destroy the player. Multiple difficulty levels can be selected which determines the number of enemies, the AI skill and damage thresholds for both players and enemies. The player aircraft carries much more ammunition than a real plane and has infinite fuel. The gameplay is simpler and more action-oriented than other combat flight simulator games. Every plane has two alternate paint schemes that are earned by shooting down enemy aces hidden in each mission.

The player has the opportunity to purchase 21 different planes including real-world production and prototype models as well as fictional planes. At the end of each mission players are ranked on their performance and awarded credits to buy new aircraft and special weapons. Special weapons including air-to-air missiles, air-to-surface missiles, rockets and bombs can also be equipped. The player's aircraft is armed with a machine gun and standard missiles that can lock on to air, ground and naval targets. Each mission features different objectives including air-to-air combat, ground attack and escorting friendly units. The player assumes the role of a fighter pilot through 18 story missions and a split screen versus mode.

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