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