There are a lot of videogames that fans would like to see made into movies, but some of those games are either fatally flawed in such a way that the transfer to the silver screen would ruin it, or so likely to run into interference from Hollywood executives that they would be unlikely to get made into good movies. Keep in mind that I'm talking about live action movies and not animated stuff because the two mediums follow different paths and have different things that can be done better or worse. So with that in mind here's a taste of the best examples...

15. Mass Effect

While there already is a Mass Effect movie in development, and it's not clear until it comes out whether or not it will be terrible, there's a lot of bad cards in the deck stacked against it. First and foremost is the question of Shephard's gender. Unless the studio decides to have a confusing movie bouncing back and forth between two alternate universes or a pair of films that do so, it's not gonna be viable to have a male and female Shephard as the protagonists. More importantly, without the ability to make the moral choices that define the shape of the plot, the film audience is going to be denied the one essential thing that makes Mass Effect so awe inspiring and significant. Further more, time is a factor that acts against the movie and there simply isn't enough of it to go around. One of the many things that makes the games so great is the amount of down time between missions that a player can take to check in with their crew. Then there's the side missions that flesh out the experience that will have to fall by the wayside. These all make Mass Effect what it is and without them an essential element is going to be lost. Finally there's the fact that Mass Effect is full of dynamic and diverse characters in a morally complex struggle that doesn't offer a lot of easy answers or clear cut distinctions between heroes and villains. Big budget Hollywood movies (and let's face it, in order to look proper Mass Effect is going to need a massive budget) often get neutered where characterization and moral ambiguity are concerned. The more money being poured in, the safer studios like to play things. Playing things safe is pretty much the opposite of what Mass Effect is about. So unless EA/Bioware are comfortable with having a cheap looking movie or have a magic lamp in their corporate vault, don't get your hopes up about a Mass Effect movie living up to the potential that can be seen in the games. There's one way I can think of to get the complexity of Commander Shepard done right. Start off with a family in the distant future (as in hundreds of years after Mass Effect) telling the tale of The Shepard. As the scene dissolves into the first scene from the story proper Shepard is introduce and he's given his assignment by Captain Anderson. The story halts and the scene returns to the family sitting at their table. The mother or grandma at the table corrects the first story teller claiming that "The Shepard" was actually a woman. The next interlude could have the camera view go next door and have a black family telling the tale and showing viewers a black male and then a black female as Shepard. There could end up being 5 or 6 or 7 actors playing Shepard as different groups of people telling the story about a legendary character who's appearance is lost to history. If you like that idea, imagine trying to explain it to a studio executive in a pitch meeting. If you're imagining any response other than derisive laughter or stern glares followed by explanations of why that would never work then I truly envy your innocence and wish that I could feel that way again without having to be magically de-aged into a 6 year old.