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