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