I finished the game ( all sixty pieces & final ) last week. It was a great experience and the story is incredibly deep. The lost princess that keeps alluding him is actually the work done to build the first atom bomb. ( The lost princess is the first atom bomb! )
It becomes clear when you read the texts carefully, and during the final ( after 60 pieces )there are quotations by opheinhimer and others from the 1940s project.

" It worked " Ophenhiemer.
" Now we're all sons of bitches " Kenneth Bainbridge after the first successful test detonation.

Tim is the evil monster chasing the princess!

The creators of this game were really smart!!