Here is the full list of all 52 Gangs of Sherwood achievements.
Finish every mission with more than one player
Kill 15 enemies by pushing or throwing them off ledges
Eliminate the Sheriff of Nottingham
Perform a Rebel Ability
Defeat The Ram
Eliminate the Prioress of Kirklees and Red Roger
Perform a Finisher
Earn an S-rank in any encounter
Be in Rebel Instinct for a combined total of 2 minutes
Grapple Attack 25 enemies
Revive an ally
Activate Rebel Instinct
Eliminate Guy of Gisborne
Perform a 100 hit combo
Launch 50 different enemies
Raise the Gang's Power to Level 4 while in any Mission
High five with an ally
Push an enemy so they fall off a ledge
Finish any Mission with more than one player
Donate 5000 Gold at the end of any Mission
Defeat an enemy by lighting them on fire
As Robin, successfully fire a total of 100 Star Arrows
Find and equip your first Artifact
Purchase an Outfit at the Remington Cole
Complete Major Oak Calls
Perform an Air Combo
Get a Headshot Kill on an enemy
Donate Gold to a Resistance's Checkpoint
Complete all the story acts on Normal difficulty
Complete all the story acts with all heroes
Kill all of Marian's siblings
Perform 15 Parry Attacks in total
As Friar Tuck, successfully perform 100 Charge Attacks
As Little John, successfully perform 100 Heat Attacks
Perform 25 Finishers
Complete the Tyrant's Pit in under 10 minutes
Perform a Throw on a enemy
Purchase the Origin Outfit at Remington Cole
Complete all the People's Requests
Unlock all Gears for all for one hero
Unlock all Gears for all for all heroes
Complete all Challenges
Complete all Lessons
Buy everything from Antonna Carridge with all Heroes
Buy everything from Antonna Carridge with one Hero
Find and equip all the different Artifacts
Find all the Gang's Mementos
Find all of Alan-a-Dale's puppets
Kill all the Crows in Edwinstowe
As Robin, get killed by the Prioress of Kirklees
Kill an enemy by throwing Gold at them
As Marian, successfully perform 100 Flux triggers