Don't shoot for whole six minutes and survive.
Stay alive at least 60 minutes.
Explode at least 100 cars in one session.
Get 10.000.000 experience points in the single session.
Kill first Undead Boss.
Rack up to 30 level.
Kill 500.000 zombies.
Kill at least 1.000 zombies with each weapon type.
Perform a rampage attack.
Use melee attack 100 times in one session.
