It stays very close to the source material. At times I feel like I need a controller in my hand. The scenes and music are clear call outs to the games and books (story is based on the books).
This is great for hardcore fans but may limit it's appeal for more general audiences. They took little creative license with Geralt and it can come off a bit flat at times.
That said, they're doing a good job of trying to flesh out a lot of characters and world history without too much exposition. I like it.