Here is the full list of all 26 SUPERHOT achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Kill over 1987 Red Dudes in endless mode.
Unlock all endless levels.
Launch every app in the system.
Become part of the community.
Beat all Challenges.
Kill 3 Red Dudes with one shotgun shot.
Get RED ending in every level of SPEEDRUNrt challenge.
Kill 100 Red Dudes with a rifle.
Upload a replay on killstagram.com
Score 100 headshots.
Kill 100 Red Dudes with a shotgun.
Get RED ending in every level of SPEEDRUN challenge.
Kill 100 Red Dudes with a katana.
Cut bullet with a katana.
Complete the game.
Find all secrets.
Get back to the system after being expelled.
Kill 2 Red Dudes with one katana throw.
Kill 100 Red Dudes with a pistol.
Kill 100 Red Dudes using melee.
Complete SERV level.
Kill 3 Red Dudes with one rifle burst.
Kill an enemy by jumping on him.
Complete SUBWAY level.
Shoot down a bullet with a bullet.