Full list of all 50 Mortal Kombat achievements worth 1,000 gamerscore. It takes around 300-500 hours to unlock all of the achievements on Xbox 360.
Complete Story Mode 50%
Unlock 50% of the Krypt
Unlock all Alternate Costumes
Perform 1 of each type of "-ality"
Perform any fighter's hidden finishing move
Discover and fight Hidden Kombatant 3 in Arcade Ladder
Win 100 total Online Matches
Complete 200 Versus matches (online OR offline)
Win both rounds with timer running out in an Online Ranked Match
Comeback with under 10% health in an Online Ranked Match
Discover and fight Hidden Kombatant 4 in Arcade Ladder
Discover and fight Hidden Kombatant 2 in Arcade Ladder
Complete Arcade Ladder with All Fighters
Perform a Fatality with all playable fighters
Perform every fighter's hidden finishing move
Unlock 100% of the Krypt
Perform every fighter's forward and backwards throws
Complete Story Mode 100%
Unlock Hidden Fighter "Quan Chi"
Unlock Mileena's 3rd Alternate Costume
Successfully land every playable fighter's X-Ray attack
Unlock Hidden Fighter "Cyber Sub-Zero"
Win Arcade Tag Ladder with robot Sektor and Cyrax
Complete all Test Your Might mini-game challenges
Complete all Test Your Sight mini-game challenges
Complete Arcade Ladder without blocking (allowed to continue)
Complete Arcade Ladder with Any Fighter
Complete all Test Your Strike mini-game challenges
Perform and land a Tag Combo
Complete 25 Tower missions
Perform 8 throws in an Online Ranked Match
Complete 100 Online Matches
Spill 10000 pints of blood
Perform a 10-hit combo with any fighter
Win A Ranked Online Match without jumping
Perform a Fatality!
Get a Flawless Victory in an Online Match
Complete Fatality Trainer
Win an Online Match
Complete Tutorial Mode
Complete Arcade Ladder on max difficulty without using a continue
Win 10 Ranked Online Matches in a row
Earn 1000 Respect Points via king of the hill matches
Earn 2500 Respect Points via king of the hill matches
Win 10 king of the hill matches in a row
Get all MK Dragons in Test Your Luck
Gain Mastery of 1 Fighter
Gain Mastery of All Fighters
Complete all Tower missions
Discover and fight Hidden Kombatant 1 in Arcade Ladder