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