Here is the full list of all 26 SUPERHOT achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Launch every app in the system.
Kill 100 Red Dudes with a shotgun.
Kill 3 Red Dudes with one shotgun shot.
Kill 100 Red Dudes with a katana.
Kill 100 Red Dudes with a rifle.
Become part of the community.
Score 100 headshots.
Kill 100 Red Dudes using melee.
Kill 2 Red Dudes with one katana throw.
Upload a replay on killstagram.com
Kill an enemy by jumping on him.
Cut bullet with a katana.
Complete the game.
Kill 100 Red Dudes with a pistol.
Kill 3 Red Dudes with one rifle burst.
Get back to the system after being expelled.
Complete SERV level.
Complete SUBWAY level.
Shoot down a bullet with a bullet.
Kill over 1987 Red Dudes in endless mode.
Unlock all endless levels.
Find all secrets.
Beat all Challenges.
Get RED ending in every level of SPEEDRUN challenge.
Get RED ending in every level of SPEEDRUNrt challenge.