Here is the full list of all 22 Arma Tactics achievements.
You have successfuly completed Bootcamp training
You have completed "Operation Tempest" campaign
You have completed the "Operation No Deal" campaign
You have killed two or more enemies at once with a single grenade
Your operators have been healed 10 times
You have killed a total of 10 enemies with a knife
You have killed a total of 25 enemies with a knife
You have killed a total of 25 enemies
You have killed a total of 50 enemies
You have found and looted a total of 15 boxes
You have killed a total of 25 enemies with a sniper rifle
You have managed to save the hostages at Dhargan Chemical Plant
You have managed to destroy communication device without being detected on your way to Soltani's hideout
You have killed a total of 100 enemies
You have completed a mission without firing a single shot
You have killed two or more enemies at once with a single mine
You have flashed two or more enemies at once with a single flashbang grenade
You have killed a total of 5 enemies with a proximity mine
Your operators have been healed 50 times
You have killed a total of 25 enemies with a shotgun
You have thrown 25 grenades
You have killed a total of 5 enemies with a remotely detonated mine