More and more films are being created from video game source material, but why are most of them so bad?

Have you ever noticed that Hollywood is a bit behind popular culture?  Think about it; people knew that comic books were rich mines of potential storylines, fantastic yet believable characters, and the kind of stuff that keep the special effects guys out of the unemployment lines for ages, but it took filmmakers a long time to finally make a decent film based on a comic book franchise.  Sure, they saw the potential for an audience in comic materials - even the Flash Gordon serials of the 1930's proved that, but it wasn't until recently that film studios realized that there was an audience for comic based films that reached beyond a bunch of kids throwing popcorn at the screen and happily uttering swear words because Mom and Dad aren't around.

For just over the past decade Hollywood has been taking a similar approach with films based upon video game properties.  Granted, when the movies first took a look at video games there wasn't a lot to work with.  They started in 1993 by making a film version of the most popular game of the late eighties: Super Mario Brothers.  Games were different then and anyone who's played Mario knows that there really wasn't a "story" per se (in fact the only dialogue of any kind until the end of the game is "thank you Mario, but our princess is in another castle") and the scriptwriters had to craft one that would be at least somewhat believable - especially with humans (Bob Hoskins, John Leguizamo, and Dennis Hopper for those keeping score on IMDB) playing the principal roles.

Super Mario Brothers was, well, not good.  It also did not do stellar box office business and it could have easily killed the entire concept of turning games into movies right there.  As gaming progressed and games became deeper, more meaningful properties with rich stories and memorable characters the game industry started to do some impressive numbers.  If there's one thing that studio execs can spot a mile away it's the potential to cash in on a popular franchise, so more films based on games were inevitable.  It was also a given that said movies would probably be terrible.

Why do movies based on games tend to be some of the worst films ever made?  There are several reasons, actually.