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