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