Secret Files: Tunguska is a German game (original title Geheimakte Tunguska) made by Fusionsphere Systems, translated to English in 2006. The game is centered around the Tunguska event and explores its cause. The main protagonist is Nina Kalenkov, a Russian girl living in Berlin, whose role is to uncover the mystery behind the disappearance of her father. At times, the role of the player-controlled character switches to Max Gruber, who is a German scientist, and Nina's father's colleague.
Because this is a German game by origin, some of the voices are a bit cheesy and don't quite fit the game. However, I really love this game and think it's one of the best adventure games ever made.
Part 2A, Part 2B
Part 3A, Part 3B, Part 3C, Part 3D
Part 6A, Part 6B
Part 7A, Part 7B
Part 8A, Part 8B
Part 10A, Part 10B
Part 13A, Part 13B
Part 14A, Part 14B, Part 14C
Part 15A, Part 15B, Part 15C, Part 15D, Part 15E
Part 16A, Part 16B, Part 16C, Part 16D, Part 16E
It seems P.M.F. is a big fan of the penguin.