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