I absolutely disagree. I started playing the first game after finishing the novels and hoped for some kind of sequel storywise. But it seemed as if the game was set in another universe. Gone was the wit and humor, what you got instead was dreary and bleak atmosphere, something that's not in the books. Sapkowski created a harsh, realistic world, not a rotten hellhole where even in the city you feel like you're crawling though a dungeon. The story was confusingly told, the huge gaps between the chapters were annoying and the whole game just doesn't feel like a Geralt of Rivia-adventure. Maybe the amnesia idea wasn't the greatest, the fact that the plot was completely detached from the events of the novels didn't help, either.
In the second game you finally got many things from the books, the kings, the lodge of sorceresses, the Nilfgaardians, the more beautiful aspects of the world. But only the third game really captures the spirit of the original material, for me it absolutely works as a continuation of the Geralt novels. The dialogues and the humour are spot on, Yennefer and Ciri finally are here, the world is rich, the stories deep, if Sapkowski weren't such a game-despising snob he would be proud of it.