Questions after the passage (Penumbra: Black Plague)

Greetings to all experts. So, after going through some questions:
1) Where in the first part there were dogs on the upper levels? Well it seems everything was swamped. And really there were so many that their Red 32 ate?
2) who and Who was dragged into the beginning of the first part (the type that spiders ate)? Clearly not a dog, because at that time, as Philip was under the floor was clearly audible that Chagall someone bipeds. There were mutants with Manwich? How? Why they did not met during the first game? Or is it the guy who was crawling in the walls of the nursery in the second part?
3) Where did the other animals (spiders, worms)?
4) About the artifacts, any coherent article is not found. What they (the pundits that he is to save - by)?
5) I understand that Philip cheated Tuurngait and sent a letter to a friend with the promise that he destroyed generally all (mutants, mines, Manwich, tomb of Tuurngait)? And he letter being sent if the connection with the outside world was not? And why even kill him? After all, he is good, is the person to blame being disturbed.
6) Before you dig up the tomb in 2000, people still went crazy. From what? Tuurngait is not there (there probably my carelessness, though I twice passed the first part, but did not understand until the end)
7) Where the entrance to Manwich? The staff through all levels of the mines were robbed?
8) what the hell need was a lake Utukak?
9) Who and for what purpose gusano GG at the end of the first part?