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