Gah. I think any year after 2011's crop of games would have seemed like a letdown, but 2012 failed in SO many ways, especially in many of its most anticipated titles.
GOTY: So far, Borderlands 2. The DLC hasn't been as good as the DLC for the original Borderlands, but it doesn't change the fact that Borderlands 2 took everything awesome about the original and turned up the amps louder than Spinal Tap, and got rid of pretty much everything that was annoying.
Best downloadable game: Fez. Seriously. Have you played it? It's nuts and in every good way.
Biggest surprise: Sleeping Dogs. It's easy to describe it as GTA: Hong Kong, but unlike GTA, I really enjoyed playing it. It has all the great moments of a vintage John Woo film and great voice performances from some talented actors.
Most disappointing: Where to start? Mass Effect 3? Forza Horizon? Assassin's Creed 3? Lollipop Chainsaw? Max Payne 3? Binary Domain? Syndicate? Inversion? Some of these weren't heavily promoted, but they started with an idea that wasn't terrible and then these games actively worked to make it terrible (see Binary Domain, Inversion and Syndicate). Lollipop Chainsaw started with ridiculous and outlandish ideas, and then beat them to death with guys saying they never expected to get rescued by a cheerleader with such great 717$. It began as a giddy romp but turned into a slog of the least pleasant parts of listening to guys in online MP invite women to join in because they need something stuck between a couple of pieces of bread. Max Payne 3 was just unnecessary in pretty much every way something can be unnecessary.
That brings us to AC3, ME3 and Forza Horizon. Forza Horizon is the worst game in the Forza series, hands down. There's a lot less to do, a lot less to drive and a lot more nonsense between races, including a terrible story that would have embarrassed Lollipop Chainsaw.
AC3 was buggy. I loved the Revolutionary War setting, but I didn't really love the game as much as I loved AC2, ACB and ACR. As long as AC3 stayed in the colonies, I enjoyed it, but by the end, it seemed to drag a bit.
And ME3 may be the single worst sequel ever made. At the very least, it's the most poorly received sequel by a rabid fan base, which made George Lucas FINALLY exhale. The hand-waving about magic at the end pretty much broke the story, and since the ME series has been all about story and continuity and play choices mattering to a ridiculous extent and allegedly factored in over 1,000 separate variables to get to one of three colors of laser on release, that hand-waving about story effectively broke the game since the game is all about the story. Seriously. Screw ME3. Someone at Bioware should have known better. At the very least, someone at Bioware should have bothered to ask "Uh, Casey? Isn't tacking the end of 2001 onto the end of Star Wars maybe going to surprise some people?" I can't take credit for that description about tacking the end of 2001 onto the end of Star Wars - I stumbled across it somewhere, but it's REALLY accurate. And if it's the case that NO ONE at Bioware bothered to ask that question - or, even more troubling, if it never occurred to anyone at Bioware to ask that question - then Bioware is in REALLY bad shape.
Best MP: Borderlands 2. The lack of competitive multiplayer doesn't bother me.
Best game I didn't finish: I can't think of a game released in 2012 that I liked and didn't finish.
2011 game played in 2012: Skyrim. Like you're surprised. That's the 2011 game everyone (except PS3 owners) played in 2012.