Under claims of false advertising and misrepresentation.
http://www.ign.com/articles/2013/05/01/ ... al-marines
For those of you who haven't been following this little boondoggle, what basically happened was that prior to the release of Colonial Marines, Sega and Gearbox released a trailer of the demo which was tagged as "actual gameplay", which showed a game that had far better graphical fidelity and AI behavior than what was delivered in the final product. Furthermore, Sega and Gearbox reps actually played this "demo" at events like E3, which turned out to be little more than an elaborate pantomime- the video game equivalent of lip-synching. Perhaps the biggest part of it, however, was that Sega effectively placed a review embargo on the game, sending no copies out to various journalist sites and publications until the game's actual release date.
So, when the actual truth fell out that Colonial Marines fell far, far short of what the "actual gameplay" and "live demo" promised, the bad reviews came in by the truckload. However, while this did help keep others away from the game, what it didn't do was help those who had actually pre-ordered the game based on the aforementioned promotions, as it had to be done sight unseen without any reviews of the actual final product available. So, now there's a class-action lawsuit. It's not one without merit or even precedent, however, as Sega has already been taken to task by the UK's Advertising Standards Authority on the subject.