Here is the full list of all 24 1166 achievements.
The Longest Journey Starts With a Single Step.
Talk to a monster...They can't be that bad, right?
See Alex at her worst.
See Alex at her worst, twice.
Talk to a cat you didn't have to talk to.
Defeat the Great Beast in the Hostel Halls. Did you run or did you fight?
Defeat the Beast that lives in your Dreams. Did you run or fight?
Defeat the Beast that stirs in the depths. Did you run or fight?
Discover the Good Ending.
Discover the Bad Ending.
Discover a Passive Ending.
Discover the all of the endings.
Follow the Candle.
Follow the Cane.
Follow the Blade.
Follow the Phone.
Follow the Cuff.
Follow the Car.
Put ??? to Sleep.
Put Marchosias to Sleep.
Put Lucas to Sleep.
Put Alex to Sleep.
Put Amy to Sleep.
Put Daudaz to Sleep.