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.
Beat all Challenges.
Upload a replay on killstagram.com
Kill 2 Red Dudes with one katana throw.
Kill 3 Red Dudes with one shotgun shot.
Get RED ending in every level of SPEEDRUNrt challenge.
Kill 100 Red Dudes with a rifle.
Get RED ending in every level of SPEEDRUN challenge.
Kill 3 Red Dudes with one rifle burst.
Score 100 headshots.
Kill an enemy by jumping on him.
Kill 100 Red Dudes with a shotgun.
Kill 100 Red Dudes with a katana.
Get back to the system after being expelled.
Kill 100 Red Dudes using melee.
Cut bullet with a katana.
Shoot down a bullet with a bullet.
Kill 100 Red Dudes with a pistol.
Complete SERV level.
Complete the game.
Complete SUBWAY level.
Kill over 1987 Red Dudes in endless mode.
Become part of the community.
Find all secrets.
Launch every app in the system.