Take it as you want to take it, for me, the developer that you expected alot from but under delivered, JUST for 2013.

Insomniac Games
Well we all know how fuse went, but the game was pretty subpar and I felt cheated £40 as I am a huge insomniac fan and wanted their first new IP in AGES to be good, but was cliched and boring.
Then not too long later they released R&C Nexus, with R&C being my first PS2 game, I was excited for it, and for the most part it was fun, but incredibly short and seemed more like a quick project than a fully fledged title. I suppose it was cheaper but I still wasn't satisfied.
Here's to a good 2014, please dont let me down.

nStigate/Nihilistic
There less than average title released in late 2012 but they showed no support for their piece of crap throughout the year, surely they could've patched some of the game breaking bugs, although now I think they're pretty much dead. 

you?

I don't know about my #1, but Activion is a nominee.

#1 EA

Square Enix for announcing that the next Final Fantasy will be a male gay pride parade.

Gearbox Software, for Aliens: Colonial Marines.

Most devs/publishers   had similar perfomances in recent years  ( EA pulling  shady crap in recent years with 2013 being the worst year| Konami being irrelevant as always| Activision making  movie-based  games that are not even worth a damn and milking the Call of Duty cow), so I can't really say that I am disappointed by any.

EA / DICE are for sure up there. BF4 release has been basically fraud / bait and switch.

GB and Colonial Marines was ridic, but I honestly never anticipated it to be good anyways.

Ubisoft.

Splinter Cell and Black Flag were major mishaps. Watch Dogs wasn't looking too great last time I saw it either.

Creative Assembly for Rome II: Total War

Nintendo, no annoucements on old ips...