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