Here is the full list of all 11 Siege Survival: Gloria Victis Prologue achievements.
Unlock Rena as a playable character.
Survive the first 7 days of the invasion.
Complete trade with any merchant at night.
End the second battle with a clear victory.
Collect all piles inside the castle.
Build enough beds for all characters.
Survive a fight during the nighttime scavenge.
Collect at least 5 units of Valuables.
Reach the enemies' maximum alert level at night.
Build all buildings available in the Prologue.
Achieve the maximum Bastion's defence power for the Prologue.