I don't play many video games so take this with a grain of salt. In fact, this year, I played 6; GTA V (ps4), InFamous Second Son (ps4), Star Wars Battlefront (ps4), Rocket League (ps4), Carcassone (phone), and Small World (phone).
I have enjoyed GTA V but, at times it is a real grind and gets kind of boring. If I don't have people to do heists or jobs with I lose interest pretty fast. I've certainly spent more time playing this game.
InFamous Second Son was a pretty fun game that followed a pretty normal end of stage big boss battle formula very successfully. I liked this game quite a bit. While I didn't get as many hours of play out of it as GTA V I probably had more fun playing it than GTA.
Rocket League was a "free" game that comes as part of my play station network account. This is basically 3-v-3 soccer with cars. I grabbed it a few months ago when it was offered but didn't get around to playing it until last month. This is a seriously fun game that you can play in 5 minute batches. It's frustratingly difficult at first but it does get easier. Plus, if you are watching someone else learn along side you it is hilarious to watch them miss easy shots (by missing the HUGE ball completely). Some people you see playing online are insanely good. I'm infinitely better than I was last month and I'm still pretty crappy at times. It's still a blast to play though. This is my favorite game of 2015 hands down.
Star Wars Battlefront is an okay game but not as much fun as I'd hoped. Mostly this is because I suck at it. More than half the time I'm being killed by someone I can't see at all. I rarely end up with a 50:50 kill:death ratio. I seriously suck at this game. I like the theme (duh) and the mechanics are okay. I think I'd probably like this better if I could play on a PC using my mouse and keyboard. The fine twitch stuff just doesn't translate well for me on the PS4 controller - especially strafe and mouse-look. It's also pretty limited in terms of content and it's missing a story mode which I would have really liked.
Small World is a board game that has been converted to online play. It's sort of like Risk - but simpler to learn, faster to play, and never results in a board being flipped in anger. The electronic version is a little buggy but still well executed. My co-workers and I played this to death and we haven't played much in the past few months. I imagine we'll get back to it before too long.
Carcassonne is another board game that was converted. The board game as a bunch of expansions and only some of those are implemented in the e-version. However, the e-version works very well (I've not encountered any bugs) and it is a quick way to enjoy the game without having to clean up the many pieces when you're done. It's fun with just two people even; Lisa and I occasionally play.
For those of you who don't want to read the entire post - my favorite game of the year was :
It's fun, quick, and easy to sneak in a game or two without dedicating yourself to long gaming sessions.