Red Faction: Armageddon is set 50 years after the events of Red Faction: Guerrilla and takes place on Mars. The player assumes the role of Darius Mason, a well-meaning individual who wants the best for his people. Unfortunately, it's not just his fault that a terrorist could destroy the machine bringing a human-friendly atmosphere to the planet, causing humans to retreat underground. He also mistakenly unleashes an hostile alien race. As a result, surviving humans are not pleased with his actions, and it's time for him to venture into the tunnels to set things right!
A significant change from its predecessor is the lack of an open world; Armageddon is a linear third-person shooter. The majority of the game involves walking through levels, killing alien masses or human cultists with a mix of conventional and science fiction weapons. Occasionally, there are boss battles and vehicle sequences, such as inside a mech. In the levels, valuable pieces of scrap can be found to trade against character or weapon upgrades. What carries over from predecessors is the destructible terrain, which can also be used towards enemy disposal. Fortunately, Darius has a device that allows him to repair his environment.
Besides the campaign, there are two additional playing modes. The destruction mode aims to earn as many points as possible within a limited time frame. Points are earned by destroying the environment. The second mode is designed for cooperative play for up to four players and consists of fighting enemy waves.