Kill the Dominator Leader.
Kill 100 Brood Warriors
Defeat the aliens in the jungle campaign.
Complete the single player campaign.
Finish the desert campaign on Extreme difficulty
Kill your first enemy in combat.
Kill the templar.
Kill the alien commander leading the resistance to the orbital assault.
Kill the last of the portal guardians and seize control of the portal to the alien home world.
Complete the first mission of the campaign.
Unlock all trophies.
Buy a high quality item.
Sell a high quality item.
Have one of your units die in battle. Ouch.
Modify your strike team.
Use a commander skill.
Have one of your units reach level 5
Have one of your units reach level 10
Build your strike team manually.
Finish the desert campaign on Extreme difficulty.