Here is the full list of all 50 Injustice: Gods Among Us Ultimate Edition achievements.
Enter Practice Mode
Defeat every Villain With Batman
Win a match as Deathstroke without missing a shot (minimum 12 shots)
Win with Batman using every special move and his Supermove
Win a match with Green Arrow using only arrows
Make a comeback when at low health (10% or less)
Send an opponent through all three Metropolis transitions in one fight
Use every interactable and win in a multiplayer match
Perform 8 throws and win in a multiplayer match
Win a multiplayer match with a timeout
Cause maximum damage in all Arenas (does not include Practice mode)
Win a Clash sequence with any character
Win all story mode minigames
Complete 100% of Story Mode
Complete 50% of Story Mode
Equip a new Icon
Win a single online match
Complete Classic Battle with any character
Reach Level 10
Get 3 stars on 1 S.T.A.R. Lab Mission
Complete 1 S.T.A.R. Lab Mission
Unlock a costume in the Archives
Unlock All costumes in the Archives
Knock an opponent through a transition
Equip a new Background Image
Equip a new Character Portrait
View Your Hero Card
Win a match with the super move of any character
Complete Classic Battle with all characters
Complete Battle Mode
Beat All S.T.A.R. Lab Missions (Excluding DLC)
Reach Level 100
Dethrone the King in an online match
Vote Correctly in a KOTH match
Defeat a Survivor
Win 100 complete Online Matches
Play 200 complete Online Matches
Win 1 complete Ranked match
Win 10 complete Ranked matches
Enter Online Practice with someone on your friends list
Complete Tutorial
Get 100 Stars in S.T.A.R. Lab Mode
Complete All S.T.A.R. Lab Missions with 3 Stars
Perform a 10 hit combo with every character
Knock opponent through all transitions across all levels
Perform every character's supermove
Perform every special move of every character
Perform every Meter Burn special move of every character
Perform every level interaction once
Unlock everything in the Archives