Let's label all the doors with numbers for better understanding.
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3241414544
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3241414631

Door 1:
Talk:
You don't sound very enthusiastic
Happiness
I can do it.
Push the lever
Key Fragment 1 received.

Door 2:
Talk:
I'm sorry.
Where do we go?
We can scream until they hear us.
I approach them.
No.
Shut up.
Key Fragment 2 received.

Door 3:
Talk:
Sure.

Play Videogame

A True Gamer, Indeed
Finish the prototype without getting hit.


https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3241399150

Talk:
It's a good start.
It's a prototype, you can improve it.
"One day"? What about your death?
Key Fragment 3 received.

Door 4:
Talk:
Get it yourself.
Attack Big Bird and take cake.
Talk:
That's not healthy.
Key Fragment 4 received.

Door 5:
Talk:
YOU tell me why.
I'm sure they're fine.
Key Fragment 5 received.

Door 6:
Talk:
Give me the last key fragment.
Key Fragment 6 received.

Last white door:
Go through all white doors forward and talk with every person.

I'm Ready
Motivate everyone.


https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3241399319

After the last conversation, choose Door 6 or Elevator. You will receive the only one storyline achievement.

My Answer
Choose your path.