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