Unknown Worlds sent us a batch of concept art from Natural Selection 2, a standalone online FPS that pits aliens against humans in a strategic and action-packed struggle for survival. Two teams of up to 16 players face off with unique abilities in dynamic, evolving environments that change as you play. You will watch spreading alien infestation deform hallways, and then use a flamethrower to clear it. You can cut the power to disable marine structures or weld a loading door shut for defense.