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