Infected 13 times (lifetime)

Complete the fifth mission of the U.S.S. campaign.

Complete the fourth mission of the U.S.S. campaign.

Purchase all abilities for one character class.

Kill an enemy with each weapon type including special weapons.

Kill an infected teammate with a headshot before they become a zombie in any mode.

Complete the second mission of the U.S.S. campaign.

Kill 5 enemies while using a zombie as a shield.