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