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.
Become part of the community.
Find all secrets.
Beat all Challenges.
Launch every app in the system.
Cut bullet with a katana.
Get RED ending in every level of SPEEDRUNrt challenge.
Get RED ending in every level of SPEEDRUN challenge.
Score 100 headshots.
Upload a replay on killstagram.com
Kill 2 Red Dudes with one katana throw.
Kill 3 Red Dudes with one shotgun shot.
Kill 100 Red Dudes with a katana.
Kill an enemy by jumping on him.
Kill 3 Red Dudes with one rifle burst.
Kill 100 Red Dudes using melee.
Kill 100 Red Dudes with a shotgun.
Kill 100 Red Dudes with a rifle.
Complete the game.
Get back to the system after being expelled.
Kill 100 Red Dudes with a pistol.
Complete SERV level.
Shoot down a bullet with a bullet.
Complete SUBWAY level.