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