Once again, I am ambivalent, but this time with a more positive overall tone.
First off, hurray for there not being as many things-crawling-into-ears as last week's preview intimated, because that shit seriously freaks me out. The cranial saw was bad enough. *shudder*
Second, hurray for the many wonderful brotherly moments, from Sam and Dean taking turns stepping in front of the other in defense, to shouting back and forth on either side of the magically-closing door, to moving in sync multiple times (I adored all four of them following the wire around the booby trap), to not being offended when the other was being suspicious of them, as I think would have been the case in the last two seasons. It really feels like the boys are back.
Third, I liked the feel of this ep, even if the title was a major spoiler. "Ten Little Indians" was the first Agatha Christie I ever read, and I loved it. That feeling of not knowing who to trust, even among the people you should trust the most, added some real suspense. (I kept having flashbacks to the X-Files episode "Ice", and I'm sure I'm not the only one.) Having Dean be the first one to lose it was a clever decision, because it meant we as the viewers couldn't trust any of them, either. (I might have given a little flail at Dean being possessed by something for the first time ever.)
I was meh about the MOTW itself. I don't think it really advanced the mytharc, I thought Eve wasn't a very good actress, and I'm annoyed at the whole idea that she created this critter just to send the Winchesters a message. Monster!Bobby was damn creepy, though.
I liked the little flashes of Robo!Sam that popped out when he was talking to or about Samuel. And as uncomfortable as the scene with electrocution!Bobby made me, it was a great character moment to have Dean be the one to administer the torture and Sam having to turn away from it. Dean admitted only two weeks ago that he shoves all of that stuff down inside him as far as he can, and it's being true to the character to let it show through now and again. Even if it makes me D:
What I hated: killing off the rest of the non-core characters. Not five seconds after Gwen becomes an ally, she's gone. Samuel, well, I guess he had it coming. At least Dean and Sam thought so. Rufus, I'm also pissed about. Not just because "somebody needs a hug" was the best line all season, but because once again, right after something more complex and interesting gets brought out, the character's dead (see also: Gwen, Henriksen, Pamela, etc.). I really wish this show would stop doing that.
Also, I am very unhappy at the upcoming hiatus, since it feels like we've just gotten back in the groove. But there were parts of the previews that had me bouncing up and down in excitement, so I hope it'll be worth it.