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