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