Accomplish the indicated achievement to get the corresponding number of Gamerscore points:

Undead Basket (10 points): Complete a survival mission only using your wrangler pack.
Zombie Assassin! (13 points): Kill 25 Zombies using your ranged weapon in online Ranked Skirmish.
Zombie Horde (20 points): Suck up 50 zombies in campaign, co-op, Ranked Multiplayer.
Frank is that YOU? (11 points): Defeat a Franken without taking any damage.
You're Not Brain Dead (4 points): Wrangle a Zombie.
Hey Doc! It's GO time! (42 points): Defeat the final boss.
New Ooze (10 points): Destroy every Gloomex canister.
Valley of Fortune (20 points): Find 20 Zombie Tarot Cards.
Staff Infection (10 points): Capture or Destroy all 10 Frozen Codebase shirt wearing zombies.
Zombification (33 points): Play online with a player who carries the infection.
Master Wrangler (13 points): Score the most ZGU's in an online Skirmish match.
Voodoo Magic (14 points): Find 20 Voodoo Dolls.