Despite Mass Effect 3's controversy surrounding its endings, Hollywood has been hot to adapt the popular action/roll-playing hybrid series into a major motion picture. Scripting duties have been handled by Mark Protosevich (Thor, I Am Legend, the upcoming Old Boy remake), with Avi Arad, Thomas Tull and Jon Jashni producing. Legendary Pictures and Warner Bros. have acquired the rights, and apparently, according to Kotaku, the script has been completed.
The science fiction series certainly seems ripe for film adaptation, however; video games often have a bizarre relationship with Hollywood, with films often turning out to be a shell of their source material. While this news is certainly exciting for fans of the series, rumors indicate that the film isn't strictly based on the game series at all (according to MSNBC). While certainly this could change in the months of re-writing and further script development, a Mass Effect story not based on the established trilogy of games doesn't make much sense.
While no doubt gamers should have faith in Legendary Pictures and Warner Brothers, as they recently closed out Christopher Nolan's Batman trilogy with The Dark Knight Rises, at the same time, gamers are expecting to see lead character Commander Shepard do battle with The Reapers, an intergalactic race of beings bent on the destruction of the galaxy. The trilogy, as it exists, does a nice job telling the story of mankind's war with The Reapers, while also affording the player multiple avenues of decision-making and storytelling. A sort-of digital Choose Your Own Adventure-style game.
A film adaptation of such a game would eliminate the decision-making of the gamer, but also could present the game's grandiose story (which, in playing time, spans around 30 to 40 hours per game) into a miniscule 2 to 3 hours. While certainly plot elements and characters can be removed or combined, there are also nuances that might be lost, interactions between the characters that might not translate well, on-screen. This is all speculation, of course, considering the film isn't even (apparently) set in the timeframe of the game.
Mass Effect - The Movie was slated to hit theatres this year, however; that's obviously not going to happen, considering the script is seemingly shelved at Legendary Pictures. Screenwriter Mark Protosevich has moved onto another project, another science fiction film, under the direction of Edgar Wright (Scott Pilgrim VS. The World) called Collider (to be produced by JJ Abrams of Star Trek and Super 8 fame) according to io9. Time will tell what the status of Mass Effect - The Movie is down the line.