If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
Zombies are attacking the White House and Obama is left to fend for himself. Find weapons and survivors to fight your way through waves of zombies until someone comes to your rescue.
W,A,S,D - To move character.
R - To reload. Space bar - To switch weapons. P - To pause game. Mouse key / Mouse button click - To aim / shoot weapon.