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