Mass Effect 2 is the second of the Mass Effect trilogy; I skipped the first game and went directly to the second one (on the advice of my video game guru, who is rarely wrong, and was certainly not wrong this time).
It is a wonderful blend of action and adventure, with a compelling story, ferocious baddies to fight, just the right number of side quests and exploration, and perhaps the most enjoyable final battle I can remember in a video game in a long, long time.
The overall game proceeds through a building stage, in which you must recruit various members of your team, and must build and explore and enhance your skills (and the skills of the members of your team). You can choose to do more or less of this, and can exit this stage at nearly any point, but I was very thorough and I recruited every member I could and finished every quest I could find.
Then you move on to the epic final sequence, which took me a solid 3 hours on a quiet Saturday morning.
An interesting part of the game is the various dialog trees, which provide real character development and force you to make some complex and thought-provoking decisions.
The voice actors are absolutely top-notch in this game, starting with Martin Sheen's voicing of The Illusive Man and continuing throughout.
It may be a ten year old game (it is a ten year old game), but it plays fresh and compelling as ever.