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