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