Here is the full list of all 23 Frontline Tactics achievements.
Swiftly defeat the enemy.
Defeat enemy elite troops.
Pepper more than one target with bullets.
First successful mission turn boys to men.
Win some missions to get feet wet.
Win a lot of missions.
Unlock a little of everything.
Crossfire is good. More is better!
Use cover and survive longer.
Kill! Kill! Kill!
Unlock everything.
Defeat enemies of flesh and bone.
Kill multiple enemies in a single burst.
Grow your squad.
Deploy and extract a full team.
Perform slice and dice kills.
Grenade fragments makes enemies bleed.
More skills are better than few.
Dual wield-r-us.
Horde a lot of credits.
Buying credits is totally OK!
Blind and stun enemies.
Knowledge is power!