Complete the following tasks to unlock Apple Game Center achievements.

Achievement	How to unlock
Boom! (20 points)	Set 1,000 zombies on fire with your grenade launcher.
Clean Sweep (20 points)	Shoot 1,000 zombies with any shotgun.
Conga Line (10 points)	Make a 10 zombie Combo kill.
Double Tap (20 points)	Shoot 1,000 zombies with any pistol.
Explorer (20 points)	Unlock all locations.
First Blood! (5 points)	Kill your first zombie.
He's behind you! (50 points)	Ride 1,000m with a boss chasing you!.
I brake for no-one (20 points)	Ride at least 5,000m in a single run.
Kangaroo (10 points)	Jump a total of 10 cars.
Massacre (50 points)	Make a 100 zombie Combo kill.
No Mercy (10 points)	Kill a total of 1,000 zombies.
Now I have a machinegun too (20 points)	Shoot 1,000 zombies with any rapid fire weapon.
Public Transport (10 points)	Jump onto a bus.
Reaper (50 points)	Kill 1,500 zombies in a single run.
Rise above the traffic (20 points)	Jump a total of 500 cars and buses.
Roadkill (20 points)	Slide 75m... on your face.
Run! (10 points)	Ride at least 1,000m in a single run.
See the world (50 points)	Travel around the world.
They're Everywhere (25 points)	Kill a total of 50,000 zombies.
Urban Pacifist (50 points)	Ride at least 1,000m without a single shot.
Wheelie Good (10 points)	Ride for 500m in one go on one wheel.