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