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If you manage follow the path to the 4th/true ending (there's already a guide here), you'll have to pass a test to get the ending. The answers are: 

-Aiden Heisenberg

-1998

-A pistol

-To prevent the ENU zone calamity

-No

Thank you so much! Started playing the true route as soon as i saw your previous post and just got to this last part.