I give the writers credit for keeping the Red Wedding's shock value, even though I knew it was coming, and while it's on a much smaller scale than in the books (e.g. the Frey forces don't charge the Northerners in the open, likely due to budget), they replaced that with intimate brutality. Heck, probably even more brutal, what with Bolton stabbing Robb ("compliments from the Lannisters"), Talisa being killed in a certain spot (I know I'm in the minority here, but I actually like Talisa's character - far more than Jeyne, who in the books is still alive) and holy shit, the acting. Michelle Fairley (the actress who plays Catelyn) did an amazing job. Her face, her wails at the end, how she just didn't have it in her to flinch after having her throat cut...excellent).
On the other hand, I can't help but be cynical about the future. This is the same problem I have with the books, and that's because Martin has played this card too often. Ned Stark dies suddenly, fine. Robb and co. die suddenly, fine. After that though, it's lost its impact. Joffrey dying, meh. Tyrion killing Tywin, satisfying, but hardly shocking. Jon being backstabbed (literally), meh. I like his character, but you can't expect to keep playing the same card and expect to get the same result. So as satisfying as it might be to see show Joffrey be poisoned, or Tyrion shoot Tywin while the latter's in a bath, the show would have to do something extraordinary to give me the punch the books were meant to have.
Which, after this episode, they might be able to. Time will tell I guess.