After I played all the way through COD5 WAW I got a unlock to play the German Zombie game... LOL
You get points for killing them (more for headshots) & you then use the points for ammo & weapon upgrades.
You can also use the points to rebuild your barriers as they get torn down by the zombies & they can come at you pretty fast in bunches.
So when it gets to that point even with shuckin & jive'n its hard to stay alive without slowing them down with the barriers...
Even after you blow their heads off they keep coming at you until you shot them in the heart! LOL
Fun game...