It seems like ages since I've played something genuinely incredible; the last game I played that I would consider to be 5 stars worthy is Spelunky, which I played at the beginning of the year. Also, I mean 5 stars in your own personal opinion, not based on GB reviews (or any other reviews).
From my gaming diary 2013:
Bully - 21st Jun - Fin 27th July 2:55pm. Loved it, especially the superb finale even though it was easy. Some of the errands were a right pain like putting kids in bins and escorting Christy back to the motel. Think I enjoyed it more than Red Dead Redemption.
Grand Theft Auto V. I only log in about once a month at this point if that but I'm hotly anticipating confirmation of a PS4 edition and played through it three times (once in a three day marathon, once watching a girl I was seeing play through it over a couple months, then playing a Real World Rules play through from start to finish for the first time in a GTA game). Los Santos is an amazing, amazing, amazing place.
Can't think of any FIVE STAR GAMES! Anyway, the last game I was playing was Warframe, I give it 4 stars baby.
I'm waiting patiently for this update to drop on ps4. I want that Katana I'll pay real money for it. This game needed a Katana so badly, and now I want a Samurai Warframe. I want to play a Kickass Ninja song while playing too.
Then I'm going to brutally Murder every enemy I see, just like Obito.
Poor Obito, he felt so much pain.
Spelunky is great, I'm still playing in hopes of doing everything possible. Otherwise I'm not sure, I loved SR4, and thought tomb raider and GTA were great I've been thinking about Dragon Age lately but I think they are all 4 stars. I would also throw Borderlands in there at 4, and I've never stopped playing that. I think the idea of 5 star perfect game should be held for nothing but the best.
I want to add Uncharted 2, not 1 or 3, just 2.
Literally just started playing SMT Devil Survivor Overclocked, and that's been great for the 4 hours I've played of it. Wolf Among Us has been absolutely amazing, but obviously not finished yet. So probably Shin Megami Tensei 4 which I played over the christmas break.
Probably Super Mario 3D World or A Link Between Worlds? I've played some decent games this year, but nothing that unequivocally blew my mind the same way those two games did. Might and Magic X may be the best Might and Magic game that would realistically be released in the year of our lord 2014, but it's also a bit rough in spots. The Banner Saga is beautiful and gloomy, but the seams of the combat begin to show before it ends. Bravely Default...? Well, most of that game is good before it falls off a cliff into the toilet.
Persona 3 FES - And I am not really even a JRPG guy. But there is something about Megaten games and especially the Persona spin-offs that just clicked with me really well. P3 is for me the most recent game I'd give a perfect score. Finished it around october last year. Now going through Nocturne\Lucifer's Call and gotta say that this one is pretty awesome as well.
I would have to say Diablo 3. I restarted as a wizard, and am having a lot of fun. What's so beautiful is that this is just the prologue for the Reaper of Souls expansion pack. DS 2 is coming up pre-order for PC, but it is in line, now. Games of recent haven't been clicking for me, so I am glad to have one or two actually in queue
I don't think I've played a 5 star game this year honestly. Probably my last one would be Gone Home and The Last of Us before that. But I think last year was a pretty great year. In addition to those two games I would rate Bioshock Infinite as a 5 star game and I haven't played a handful of major releases still. In 2012 I think the only 5 star game I would mention would be Journey.