Campaign mode presents you with 15 increasingly larger cities to protect from zombies, rogue militia members, raging fires, huge spiders, killer bees, time bombs, and several other threats to the well-being of the taxpaying citizens. Eradicating these pesky party crashers is as simple as flying into them. Of course, you'll need to hit them with some force, lest you simply bump them to another part of a building where they'll continue to wreak havoc. Flying around the board, you follow tiny arrows that indicate the presence of a threat. The size of the arrow indicates the significance of the threat. Blinking arrows are more urgent, and blue arrows indicate a frozen threat, which comes about by unlocking and activating new powers.