Here is the full list of all 30 Comrades and Barons: Gates of Freedom achievements.
Win "Battle for Valmiera" of the first scenario
Win "Battle of Inčukalns" of the first scenario
Win "Tauwetter" of the second scenario
Win "Eisgang" of the second scenario
Win "Frühlingswind" of the second scenario
Win "Liberation of Jelgava" of the second scenario
Win "Fights near Bauska" of the third scenario
Win "Liberation of Rīga" of the third scenario
Win "First clash at Cēsis" of the third scenario
Win "German offensive" of the fourth scenario
Win "Estonian counterattack" of the fourth scenario
Win "Jugla battles" of the fourth scenario
Win "Western Army strikes" of the fifth scenario
Win "Bolderāja landing" of the fifth scenario
Win "Latvians attack" of the fifth scenario
Win "Liberation of Rīga" of the fifth scenario
Win "Defense of Liepāja" of the fifth scenario
Win "Liberation of Jelgava" of the fifth scenario
Win "Prologue" of the sixth scenario
Win "Operation in the south" of the sixth scenario
Win "Operation in the north" of the sixth scenario
Win "Liberation of Rēzekne" of the sixth scenario
Win every scenario
Run out of time and lose
Win a combat by drawing an armoured car card
Win a combat by drawing an aircraft card
Disperse a frontline unit
Disperse a regiment's headquarters
Disperse a brigade's headquarters
Disperse a division's headquarters