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