Long ago, humanity was ambushed by a mysterious alien race. Many perished—while those who survived were forced to find refuge in the mountains. Many years have passed, and the survivors cannot continue their refuge in the mountains. They must return home...

Play as MARS (Machine of Absolute Retaliation and Safeguard), a robot programmed to exterminate the treacherous aliens who have taken over Razor City. As MARS, you must free Razor City from its domination in order to save the survivors from their doom.

In DarkStorm, you must fight endless waves of aliens. As you pass each wave, the map grows larger, allowing you to explore more. Random collectibles will be spawned throughout the map, including health, ammo, weapon upgrades, and random weapon crates. There are three types of enemies, a Bat, Brute, and Crab. Each enemy has a special set of skills, so you have to watch out as you fighting them. The game includes only one gamemode, which is the endless wave. Once you pass wave 8, the map is completely open for you to explore.