Complete the indicated task to unlock the achievement.

Achievement	How to unlock
Bloody Carnage	Complete the story on "Normal" difficulty.
Boner	Kill 1000 Skeleton Army.
Bored?	Played all modes.
Bring The Peace	Shoot 250000 bullets.
Carnage	Complete the story on "Easy" difficulty.
Dead No Longer Walking	Kill 1000 Zombies.
Dino Crisis	Complete Mesozoic Era on story.
Do Not Compute	Kill 1000 Robots.
Frozen	Complete 4th Century BC on story.
Greedy	Unlock all the weapons.
Headmaster	Get 500 Headshots.
I'm Not That Bad	Achieve Bronze in all challenges.
I'm Pretty Good	Achieve Silver in all challenges.
I'm the Dogs B	Achieve Gold in all challenges.
Mexican Wave	Survive 25 waves in Arcade.
Mr Robot	Complete 6th Millennium on story.
Perky	Unlock all the perks.
SSTORM	Complete the story on "Hard" difficulty.
Shoot Her	Kill 1000 Dinosaurs.
Slippery Devil	Take no damage for an entire level in the story mode.
Zombie Nation	Complete 4th Millennium on story.