Treasure Domination
Win a Plunder game without letting the opposing team score (5-0)

And Stay Down!
Win 50 matches of Elimination

Omnipotent
Complete a Co-op Adventure Map on Crushing Difficulty without losing a single life

All Together Now
Kill the three end bosses in Chapter 5 (Harry Flynn, Eddy Raja, Zoran Lazarevic) within 20 seconds of each other on Hard

Air Mail
Get 25 Return To Sender Medals

Statuesque
Get the Curator Medal while on Hard Difficulty

Payback is a…
Get 50 Retaliation Medals

Colonizer
Get 50 Expansionist Medals

Everyday I'm Tauntin'
Get 50 In Your Face Medals

How's That Taste?
Get 50 Fisticuffs Medals