I don't consider Requiem as a part of the actual story. I think of it more as a 'what could of happened expansion. I feel like it was made just to satisfy everyone on the forums who kept asking, "what happened?". A good game leaves the player wanting more or asking questions, by adding Requiem I think they took that away. Plus the voice acting wasn't the same to me. I felt like the whole expansion was forced.
Anyways, I guess if you look at it in a different point of view it was kinda fun to solve the puzzles and play with the physics some. I just wish it didn't carry the Penumbra title.