Here is the full list of all 54 Forts achievements.
The base game contains 21 achievements, and there are 2 DLC packs containing 33 achievements.
Win the Moonshot boss battle
Win the Moonshot boss battle (Hard)
Unlock all Moonshot weapons
Unlock all Moonshot weapons (Hard)
Complete all campaign objectives
Complete all campaign objectives (Hard)
Complete all Japan objectives
Complete all Japan objectives (Hard)
Complete all Indonesian objectives
Complete all Indonesian objectives (Hard)
Complete all New Zealand objectives
Complete all New Zealand objectives (Hard)
Complete all Australia objectives
Complete all Australia objectives (Hard)
Play a multiplayer battle using the Buster Commander
Play a multiplayer battle using the Phantom Commander
Play a multiplayer battle with Moonshine Commander
Host 5 Moonshot multiplayer battles
Win a capture point map with your blastdoor open
Win the High Seas boss battle
Win the High Seas boss battle (Hard)
Unlock all High Seas weapons
Unlock all High Seas weapons (Hard)
Complete all Part 1 objectives
Complete all Part 1 objectives (Hard)
Complete all Part 2 objectives
Complete all Part 2 objectives (Hard)
Complete all Part 3 objectives
Complete all Part 3 objectives (Hard)
Host 5 High Seas multiplayer battles
Host 10 High Seas multiplayer battles