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