Kill 100 zombies.
Kill 500 zombies.
Kill 50 special zombies.
Reach level 11.
Reach level 22.
Kill 100 zombies with a pistol.
Kill 100 zombies with an SMG.
Kill 100 zombies with a rifle.
Kill 100 zombies with a shotgun.
Walk 200 metres
Walk 2000 metres
Walk 20000 metres