8-Bit Invaders is the second standalone expansion for 8-Bit Armies, and is fully compatible in multiplayer with both the base game and 8-Bit Hordes, the first standalone expansion. Two new factions are introduced: the Galactic Marine Corps and the alien Cranioids.
The story revolves around an intergalactic war between humans and aliens, where players take on the role of a commander leading their faction to victory. The campaign missions provide a narrative drive for the gameplay, as players progress through levels and complete objectives to turn the tide of the war.