After all the "better than Forza and Gran Turismo" articles, it just wasn't, not even close. True, you can get a stable frame rate on pc and it's most likely a lot better with a proper steering wheel (after you figure out how to set it up). Yet the AI would still suck with inconsistent difficulty levels and the lack of feedback due to missing tire sounds is a big mistake. There were plenty complaints on Steam as well, yet the media http://www.eurogamer.net/articles/2014-09-05-project-cars-is-already-a-better-racing-game-than-forza-or-gran-turismo
But yes, it was a bigger disappointment on consoles as they didn't even bother to configure proper controller support. There are tons of guides online how to configure all the different sensitivities, deadzones and filtering settings, yet there is no 1 fix for all cars. Kinda ridiculous you have to change the controller settings for different cars.

J Stars Victory Vs+, FUCK YOU SPIKE CHUNSOFT

Mario Tennis: Ultra Trash

For me, it was all nintendo. The delays hurt, and (if marketed properly) I felt they had a great chance to move some wii u's with super Mario maker and their lineup (which is likely being pushed back to fill next year's gap) riding on the success of Splatoon. Really, their ancient policies towards youtube are just killing them, flushing away endless free advertising and receiving only bad press in return.

It's pretty much set in stone, now. Each console, in a way, gets exactly what it deserves, but this is one that will go criminally under appreciated, and nintendo have only themselves to blame.

Fallout 4? if that's your disappointment then you've got way too high expectations. when we consider things that have come out like Battlefront, Halo, the newest Call of Duty, The Order 1886, Tony Hawk, etc.

there have been a ton of shit big releases and Fallout comes nowhere near the others. it doesn't lack content or quality like they do

I don't have a racing wheel, not comfortable on the couch. I played it for a few weeks with different controller settings for different cars. It was driveable but far from the enjoyment of GT and Forza with a controller. And the AI was terrible, ignoring rain, going over the grass without penalties or any negative effects, creating huge traffic jams and getting stuck blocking the road. They praise the realism of no tire squeel, yet without out it you have no proper feedback for losing traction. The rumble is not precise at all.
I played it at release with all the bugs, I might get back to it when I have some time. The release version left a bitter aftertaste though. Still tracks like Zolder were fun to experience for the first time.

Can't say I was really disappointed in anything this year: I'm wary of most releases nowadays and try to get a sense of a game's quality based on internet discussion.

I forgot to mention the new Nintendo 3ds

Minecraft story mode

Nothing I've played this year has disappointed me, but my brother ranted throughout his play through of Arkham Knight, and didn't stop ranting for weeks after