The game shares many features with the earlier Defender and Stargate in that play takes place in a horizontally-scrolling play field above a planet's surface on which humans are under attack from alien invaders. In all three games the player gains points and other advantages from protecting and rescuing humans from these attacks.
Strike Force adds several new features; two players may share the screen at one time, the surface of the planet is littered with various special weapons that can be picked up and deployed, and humans can be "mutated" into small green creatures that will fight against the player (although the player may still pick them up for points as with the unmutated humans). The mutants may use vehicles found on the planet's surface against the player.
One weapon the player may deploy is the commando, who will hang off the bottom of the player's craft shooting at enemies, or drop to the surface to pick up humans, mutants, or weapons for the player. Many commandos can be in play at once.