You Finished World 1 - Prehistoric.
Kill 30 Zombies with your dual pistol
Nice guys finish last.... or dead. You shot Mad Dog before the 10 count.
Kill 10 Zombies with a single Grenade
Let 20 Zombies get killed by train in level 2
Kill 50 Zombies with a Buzzsaw
Bound by honor, you're a true man of the west. You waited until the 10 count and still beat Mad Dog.
Kill 10 Zombies with a single Mine
Kill 65 Zombies with a Single Sentry-Gun
Take out 10 Zombies with the blast from another exploding Zombie.
You finished World #2 - The 1930's
You finished World 3 - Egypt.
Finish the Story Mode in one sitting without having to use a continue! (Clicking Retry Level or going back to Main Menu)
You finished World 4 - Japan
You completed the story mode of the game.
Kill 50 Zombies with a Shotgun Pickup.
Get 75% or greater accuracy on any Chapter.
Earn a 100x combo from any weapon pickup.
Kill 10 Zombies with a single Bazooka Shot
Kill 20 zombies without moving.
Survive to Wave 15 on any Survival Mode map.
Finish all levels without dying once. (You can replay individual levels)
Kill 100 Zombies with a Buzzsaw, whilst wearing a shield!
Kill 125 Zombies with an SMG Pickup.
Kill 50,000 Zombies Total.
Kill 125 Zombies with a Mini-gun Pickup.
Kill 10 Zombies with a single rifle shot.
Kill Mad Dog and bring the law back to this desolate western town!
Last 30 Seconds without killing a single Zombie.
Kill 50 Zombies with a Flamethrower Pickup.
Finish any level by only firing the pistol.
Let the T-Rex kill 10 Zombies in one hit with it's shockwave blast.
Kill 10 zombies with a single dynamite throw.