I think it's the same problem with Max Payne. I haven't watched it yet though, but hearing the bad criticism, I see the same problem when going from one medium to another. What works in the first one doesn't necessarily work in the next one, simple as that. To make 20CB or Max Payne work as movies, maybe they have to be changed quite a lot, and then what is the point, just make a new story that fits the movie format better in the first place. It's like coke, it worked very well as a drink, so why don't we make "Coke bread"? We don't because we expect other properties of the bread. There are of course cases where a story could work in several media, but for instance in 20CB and Max Payne's cases they both have interesting stories but at the same time I think they owe a lot by being a manga or being a game.
