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