Complete the indicated task to unlock the achievement.

Achievement	How to unlock
Back to Retirement	Defeat Julius Steelwell and save the world by destroying The Butler.
Can't Touch This	Complete an area in Katharsis without getting hit.
Gladiator	Clear all Survival mode arenas.
Green Peace	Don't push over any trees in Trespassers.
Iron Man	Learn how to operate your walker and complete Bootcamp.
Mine! Mine! Mine!	Don't take any damage from sea mines in Tide of Battle.
Second in Command	Defeat General Brutus by destroying The Excavator.
Survival of the Fittest	Complete a Survival mode arena without losing a life.
Take it to the Max	Fully upgrade your walker.
Thunder Struck	Destroy all lightning harvesters in Fog of War.
Veteran	Complete all areas on the hardest difficulty.
You Never Walk Alone	Complete an area in co-op.