It certainly lived up to the moniker of 'Red Wedding' ...
Seeing Grey Worm was awesome, even more so when set against the knight and the mercenary ... three distinct fighting styles, shown off brilliantly.
Jon and Ygritte - I did not see that playing out they way it did in that episode.
Bran and Rickon - For as little effort the the series has put into these two, their parting scene was really well done.
Talisa - Totally bummed, she had the best body I thought of those that liked to show off in the series.
Grey Wind - it was very sad to watch his end, especially since he didn't get to fight back.
Brynden "Blackfish" Tully - I hope he survived, he wasn't in the hall since he went to take a piss. They didn't show him getting it like the rest of the guards after the fact (or if he did, I missed it).
The look on Frey's face during the slaughter was damn creepy, he did a hell of a job.
I agree with Sumo on the Hound, he is getting better and better much like Jaime.