I haven't seen the film and I didn't read the book but, as far as I know, The Da Vinci Code had everything to be succesfuly turned into a game. After all, it's an epic atmospheric puzzle with a backstory about conspiracy theories. So I was not surprised when they released the tie-in PS2/XboX/PC game. In fact, Dan Brown's story could have been a game in its original incarnation, as almost every element required was already there (well, maybe except the most important ones - interactivity, agency, etc. But you got the point).
However, I was surprised to find out about The Da Vinci Code casual game. For a second, I was a little bit shocked: How much are casual game developers willing to pay for licensing, now? Maybe I am wrong, but I thought the low-budget model inspired (or forced) developers to create original IPs.
But the move makes perfect sense: The Da Vinci Code (the book) presented a literary puzzle-adventure and reached the masses - the same audience that, it is claimed, plays casual games. If the casual market is as big as it's supposed to be, and given the success of the book, TDVC casual game has all the conditions necessary for selling quite a lot.
I can't put my finger on it, but something feels upside down in this story.
PS: can you imagine how popular The Da Vinci Code interactive storyworld could become?