Few minutes after the beginning the game you have to resolve a puzzle to lower an individual to the ground floor.
From there, you can move it around the main room to 3 different exits :
- One is just a dead-end
- Second exit the room with a "shell shaped arm" -> using it will unlock the 002 Achievement
- Third exit is the room with the saw ( the saw is kind of hidden behind the "chair" )-> using it will unlock the 001 Achievement.
To get the 2 Achievements,
I think 2 playthrough are required
Thanks to Videatur's comment : "It is not necessary to do two runs. Once you have made an achievements restart save, will restart from the checkpoint created once you arrive in the great room and you will have to retract your "assistant" down, at which point do the other achievement."
Don't hesitate to correct me and I'll update this guide.
This is my first guide, please be gentle