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