The following review may contain mild spoilers for Mass Effect 3. If you're sensitive to such things, please skip to the Co-Op portion of the review which begins on page 3.
The Reapers have come. Commander Shepard's big "I told you so" moment arrives in a terrifying way: Earth has been decimated, and the rest of the galaxy is being overrun. Current technology can only stave off the Reaper advance, and the disparate fleets of the Alliance and Council races cannot survive on their own. It's up to Shepard to not only try and formulate a plan to save everyone, but to unite all of the species in the galaxy under one banner to try and defeat the Reapers once and for all. It's simple: live together, or die alone. Victory at any cost.
My Shepard is not your Shepard. For five years now, I've roleplayed the most ass-kicking space lady this side of Private Vasquez and somehow also managed to become the greatest diplomat in the universe. Your Shepard might be a bald space marine with a short temper and a penchant for shooting people in the face, or a man determined to succeed, no matter what sacrifices must be made. My party members are old soldiers, old friends. I care about them. The game capitalized on this in ways that can be surprisingly touching.
Mass Effect 3 has a feeling of finality that persists throughout. Story arcs that were seeded in prior games reach their conclusion. Decisions you made back in 2007 with the original game can come back to haunt you, or gambles you made might pay off spectacularly. Characters you've met in the past (granted you managed to keep them alive) again cross your path. Sometimes they'll join your desperate fight, but often they have their own problems to deal with. Again, their personal stories are wrapped up, and not always for the best. The sheer number of loose ends that get tied up during the 30-hour (for me, anyway) campaign is almost startling. For those of you who played the DLC episodes for both prior games, there are some interesting pay-offs that other players might not catch.
As you might have heard, the last ten minutes of the game or so are incredibly polarizing, but while I understand and even agree with (some of) the criticism, I didn't feel like the nearly 100 hours I've spent with these characters and this universe have been wasted, nor will I be calling for the King's Justice to be meted out on Bioware.