Lately, I cannot stop playing Mass Effect 2. I find it to be one of the most incredible experiences in the history of gaming. Everything about the game -- the story, graphics, audio (especially the voiceovers), animations -- is top notch. Bioware consistently overwhelms me with their ability to tell intelligent stories with such emotion and sincerity. If Mass Effect 2 were a movie, I would consider it one of the best science fiction films of all-time. This really speaks to the game's ability to draw players in with convincing characters and a profound, relevant plotline.
At this early point in time, I would have to argue that Mass Effect 2 will undoubtedly be Game of the Year. I don't foresee any of the anticipated games in the pipeline even coming close to the quality of this Bioware masterpiece. If you haven't tried this or the first game in the series, go out and pick them up. They are truly treasures of gaming. I would rate the first game 9/10 (stupid driving missions put a damper on the experience), while I can't give the second one anything less than a 10/10 (at least up to the point I've reached, which is about 22 hours in). I believe that, by the time I complete Mass Effect 2, it will be second only to The Legend of Zelda: Ocarina of Time on my all-time favorite games list.
