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