The Critical Mass 15mm rule system is a fast play alternative action company level game. Infantry are based in multiples and form platoons, vehicles are based individually and grouped to form units. Each game round players must manage their units activations with play continually moving back and forth as each unit is activated meaning games a tense and involved. As you would expect from a sci-fi game Walkers, Drop Troops, Grav Tanks, and much more are a plenty, coupled with lots destruction and mission defined battlefield objectives. —description from publisher