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