Here is the full list of all 26 SUPERHOT achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Find all secrets.
Beat all Challenges.
Kill over 1987 Red Dudes in endless mode.
Unlock all endless levels.
Get RED ending in every level of SPEEDRUNrt challenge.
Kill 100 Red Dudes with a rifle.
Kill 3 Red Dudes with one rifle burst.
Get RED ending in every level of SPEEDRUN challenge.
Kill 100 Red Dudes with a katana.
Complete SUBWAY level.
Launch every app in the system.
Complete the game.
Kill 100 Red Dudes with a shotgun.
Kill 100 Red Dudes using melee.
Score 100 headshots.
Upload a replay on killstagram.com
Get back to the system after being expelled.
Kill 3 Red Dudes with one shotgun shot.
Kill 100 Red Dudes with a pistol.
Cut bullet with a katana.
Kill an enemy by jumping on him.
Become part of the community.
Complete SERV level.
Kill 2 Red Dudes with one katana throw.
Shoot down a bullet with a bullet.