If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
There are absolutely No Mutants Allowed to the enter ground of your area. In this fast-paced strategy game you have to defend your base at all costs. Use your special abilities and shooting powers to kill all mutated attackers before they can break through the barricades. Gain enough cash to purchase tons of upgrades between the battles or hire more humans to back you up.