You finished World 5 (Future)
You finished World 4 (Japan)
You finished World 3 (Egypt)
You killed 50 Zombies with a Buzzsaw
You finished World 2 (The 1930's)
You earned a 100x or more combo from any weapon pickup
You Finished World 1 (Prehistoric)
You killed 10 Zombies with a single Grenade
You killed 20 zombies without moving
Survive to Wave 15 on any Survival Mode map
Get 75% or greater accuracy on any Chapter
You finished World 6 (Western)
Finish the Story Mode in one sitting without having to use a continue!
Finish the game without dying once
You finished a level by only firing the pistol
