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