Here is the full list of all 50 Mortal Kombat vs DC Universe achievements worth 1,000 gamerscore.
Perform Klose Kombat
Perform a Free-Fall Transition
Perform a Fatality!
Perform All Super Moves and Promoves
Complete All Kombo Challenges
Complete Catwoman's Kombo Challenge
Complete Shang Tsung's Kombo Challenge
Complete Kitana's Kombo Challenge
Complete Raiden's Kombo Challenge
Complete Deathstroke's Kombo Challenge
Complete Lex Luthor's Kombo Challenge
Complete Superman's Kombo Challenge
Complete Wonder Woman's Kombo Challenge
Complete Kano's Kombo Challenge
Complete Green Lantern's Kombo Challenge
Complete the Flash's Kombo Challenge
Complete Batman's Kombo Challenge
Complete Darkseid's Kombo Challenge
Complete the Joker's Kombo Challenge
Complete Sonya's Kombo Challenge
Complete Liu Kang's Kombo Challenge
Complete Scorpion's Kombo Challenge
Complete Shao Kahn's Kombo Challenge
Complete Baraka's Kombo Challenge
Complete Jax's Kombo Challenge
Complete Arcade Mode with all DC Universe Characters
Perform all Fatalities and Heroic Brutalities
Finish arcade mode with a DC character
Complete Arcade Mode with all Mortal Kombat Characters
Perform a Heroic Brutality!
Perform a 10-hit combo in Arcade Mode
Complete Captain Marvel's Kombo Challenge
Complete DC Universe Story
Complete Both Mortal Kombat and DC Universe Stories
Complete Chapter 5 - DC Universe
Complete Chapter 3 - DC Universe
Complete Chapter 1 - DC Universe
Complete Mortal Kombat Story
Complete Chapter 5 - Mortal Kombat
Complete Chapter 3 - Mortal Kombat
Complete Chapter 1 - Mortal Kombat
Finish arcade mode with an MK character
Complete Sub-Zero's Kombo Challenge
Play 200 Versus Matches
Beat Arcade Max without using a continue
Win a Chat Room Match Online
Play 10 Ranked Matches Online
Win 25 Ranked Matches in a row
Play 100 Chat Lobby Matches Online
Get a Flawless Victory Online