Also the other way around, good or great movies often make horrible games cause they not well thought out..
As for the topic at hand, there are way to many blanks in game to movie adaptations, and this puts the movie goer at a lost especially if they havent played the game or have a slight basis to what is happening. The Resident Evil franchise for example tried its best to explain things, but even i was confused at times with the gap in storylines... I love the games and love the movies to including the animation ones. I think game developers and writer need to sit side by side writing and the director should play the game and see what make it tick and try and bring that out on the Big screen.