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