Here is the full list of all 15 Strategy & Tactics: Wargame Collection achievements.
Complete 1 mission in any campaign with a gold medal
«The Birth of Tragedy»
«Eastern Front»
«Roads of Freedom»
«Victory Day»
«Twilight of the Gods»
Complete 15 missions in different campaigns with gold medal
Complete all 33 missions in all campaigns with gold medals
Complete any 10 scenarios with gold medals
Destroy 12 tank divisions in one turn
Spend 10000 technology points
Earn rank 10
Play 1000 turns
Spend over 9000 resources
Lose 100 divisions