Here is the full list of all 20 Line of Defense Tactics achievements worth 1,000 gamerscore.
Complete the tutorial mission of the Lyrius campaign.
Destroy all red crates in a mission. Cannot be completed in tutorial mission.
Dock the GCV Starguard with Arkangel station.
Complete the first 8 missions of the Lyrius Campaign.
Complete all Lyrius campaign missions on Normal.
Complete all Lyrius campaign missions on Hard.
Purchase your first CTC.
Unlock all CTCs on a single character.
Unlock all weapons, CTCs and items on a single character.
Complete a mission without taking damage.
Eliminate 20 Insurgents using melee combat.
Eliminate 100 Insurgents with sniper head shots.
Use 10 airstrikes.
Perform 25 uses of the Medical Kit.
Perform 25 BIO-HUMAN revives.
Destroy 20 asteroids.
Kill 40 or more enemies in a single skirmish.
Complete all secondary and optional objectives in the campaign.
Eliminate 10 Insurgent vehicles during campaign missions.
Perform 10 uses of the Repair Kit.