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