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