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