Video Game plots don't translate well to movies. They're either too long with a very linear progression of events, or something like Mario where it's pretty much just A to B with a few boss fights. What's very compelling and fun in a game is boring in a noninteractive medium.
On a related note, George A Romero wrote a script for the Resident Evil movie, that was actually faithful to the game, and then they went with the other guy. I lie awake a night imagining how much better that movie could have been.
"Now, a fun game should always be easy to understand - you should be able to take one look at it and know what you have to do straight away. It should be so well constructed that you can tell at a glance what your goal is and, even if you don’t succeed, you’ll blame yourself rather than the game. Moreover, the people standing around watching the game have also got to be able to enjoy it." - Shiggy
