The saga of a Halo movie is long and twisty. There was real "heat" on the project back in 2006. Alex Garland (28 Days Later) was commissioned by Microsoft to write a script. Fox and Universal reportedly ponied up $5 million to purchase the film rights. Peter Jackson was signed on to produce. Neil (District 9) Blomkamp was ready to direct. But then, a ton of Hollywood politics, conflicts over money and other issues put the project on the proverbial back burner, where it has languish to this day.
But there is still a possibility of a Halo movie. According to The Vulture, Steven Spielberg's DreamWorks is considering making a Halo film, but it won't be based on the games. Instead, it will be based on the Halo novels, allowing the potential production to neatly side-step the legal and financial mess the original Halo movie has turned into.
Basically, if this scenario is true, DreamWorks is saying: "Our movie would based on these novels. It has nothing to do with the massively popular video game series your movie is based on."
While it nice to think of Spielberg producing (directing?) a Halo film, there may be a big obstacle in the way of the project: Microsoft. According to The Vulture's unnamed source: “Microsoft] doesn’t want anything to happen in any other media that could screw up a multi-billion dollar franchise. Somebody has to be in control of a movie; it’s a director’s medium. But they’re completely averse to that. Because if Steven Spielberg f*cks it up, what’s your recourse? So the rule is: ‘First, do no harm.’”
I can totally do without a Halo movie. You know why? Because Halo is a series of games. It's fun and awesome because I'm shooting aliens in the face. The interactivity is the entire ball of Halo wax.
Also: Movies based on video games are (almost) always horrible. Past experience tells us that the best we could reasonably expect is a Tomb Raider level mediocrity.
Source: The Vulture