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