Enemies come in three main varieties. "Scuttlers" are small Things formed from the limbs and appendages of infected personnel. They are fast, but weak, and can be killed simply by shooting. "Walkers" are larger than scuttlers, and much stronger. To kill them, the player must weaken them using gunfire before then using the flamethrower, as only fire can completely kill them. Bosses are larger and much more powerful than Walkers, and although each one requires a specific strategy to defeat, the principle is the same; weaken it with gunfire before burning it.