2013's biggest game
I never believed it could be, but Aliens: Colonial Marines may very well end up becoming the biggest game of 2013. The game looks like it has the thrilling action of classic shooters like Doom, combined with the atmosphere and tension of survival horror games such as Resident Evil.
The Alien franchise as a whole has experienced a resurrection of sorts, thanks mostly to Prometheus. Unlike the Alien vs. Predator franchise, which I personally do not enjoy, A:CM is a true sequel and continuation of the original Alien trilogy and I believe it will tie up all the loose ends together and bring to some sort of sensible close the saga of Ellen Ripley.
After the game is released and depending on how well it does, I actually would not mind seeing James Cameron step up once more create a movie based on A:CM. But I am getting ahead of myself here. :)