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