Here is the full list of all 25 The Hidden and Unknown achievements.
Sometimes, choice is only an illusion.
The future is not so bright, if you don't fight.
The "Good" Old Times.
The Bottom.
The Rock Bottom.
From The Bottom To The Top.
The Real Challenge, or is it?
You are close.
You got far.
This is the end, or is it?
You have read the credits.
You have read it all.
Think.
The Black Swan.
The Blitzkrieg.
Efficiency.
Think first.
Feel.
Depression.
Love.
Hate.
Feel second.
Thinking without Feeling is pointless.
Feeling without Thinking is dangerous.
You have read all the main storylines in the game.