Here is the full list of all 12 Harms Way achievements worth 200 gamerscore. It takes around 1-2 hours to unlock all of the achievements on Xbox 360.
Get the missile launcher for the first time
Deploy mines for the first time
Shoot and takeover an enemy turret
Activate a turret downgrade powerup
Host a multiplayer game for the first time
Join a multiplayer game for the first time
Just look at credits
Win a game in Single Player
Wreck an opponent as a shooter
Hit the windshield of a driver
Hit the tires of a driver
Wreck your vehicle