Here is the full list of all 41 Siege Survival: Gloria Victis achievements.
Finish the scenario without loosing any survivor.
Complete the main storyline in one of the following scenarios: Story, Quick start, or Explorer.
Keep the defence so firm, the relief forces completely smash the enemy.
Reach 75 points of the the Bastion strength.
Galvik survives and returns to the Bastion.
Kill 3 enemy guards during a single night.
Provide the soldiers with enough food that they get a boost
Reach 50 points of the the Bastion strength.
Build enough beds for all characters.
Craft a heavy armour using the upgraded Armoury.
Unlock Jacob as a playable character.
Use the trebuchet during a battle.
Craft a sword using the upgraded Armoury.
Prepare for using the trebuchet by scoring 4 points in scouting before a battle.
Send out at least 2 characters to scout the enemy lines at night.
During an enemy assault exceed their strength so much, they will flee from the battlefield.
Manage a party of 4 characters at once.
Unlock Rose as a playable character.
Unlock all the scavenge starting point during a single scenario.
Join any new character to your group.
Unlock Gerard as a playable character.
Survivalist unlocked scenario is now available for you to play
Scavenger unlocked scenario is now available for you to play
Defender unlocked scenario is now available for you to play
Survive the first 7 days of the invasion.
Survive a fight during the nighttime scavenge.
Kill an enemy guard at night.
Complete trade with any merchant at night.
Collect all piles inside the castle.
Quick Start scenario is now available for you to play
Explorer scenario is now available for you to play
Unlock Rena as a playable character.
Complete the Scavenger scenario.
Complete the Defender scenario.
Complete the Survivalist scenario.
Win all battles of the whole scenario.
Unlock all available playable characters.
Unlock Demetrius as a playable character.
Unlock Mikel as a playable character.
Unlock Kimbra as a playable character.
Find and collect all the treasure chests available in the whole scenario.