The main plot of this episode, such as it is, is am even more confused mess than part one. The Doctor is duplicated and it's pretty obvious that there's going to be some twist later on where it turns out everyone's confused about which Doctor is which (and there is), and there's a whole lot of fucking around where the humans and the doppels try to escape and get each other killed, and another completely unsurprising twist where it turns out Rory's friend has been a doppel the whole time.
Once again everyone seems to be homicidal for no apparent reason, except for Rory's friend who now apparently has the excuse that she's got the memories of the doppels who've died before or something, so now she's crazy. So she chases them around and they reach the TARDIS just in time, with a couple of people being completely killed off and the remaining ones nobly sacrificing themselves
Particularly grating is the bit where the doppel Doctor sacrifices himself at the end because he has to hold the doors so the others have a chance to get away, only everyone just stands around chatting for a while, and no one's even holding the fucking doors, so everyone could easily have gotten into the TARDIS and he only stayed behind to make sure he was disposed of and there was only one of each person left.
Oh, and it turns out Amy's been a doppel this whole time, and the real Amy's pregnant, which is why the TARDIS medical scanner
Seriously, the TARDIS couldn't even tell what species she was? No wonder it was confused about the pregnancy, it can't tell humans from copies made out of goop. Oh, and Amy accidentally told the Doctor about seeing him die, which will either be a major plot point or be completely ignored next week.
I do find it amusing though that apparently neither Amy nor Rory have been human for a while now, although it would be better if Amy stayed Flesh forever, but they're going to bring human Amy back.
Oh, and the bits where the Doctor was talking to the doppel Doctor were quite entertaining, so points for that. And I did like the bit where he kept quoting previous incarnations, and hearing Tom Baker was a bit of a surprise. Although it would have been cool if his face had shifted between some of them. Couldn't you at least get Peter Davison to come in for a cameo? He was in that charity special a few years ago. And I must admit that even though I know it's going to be shit, I am intrigued and want to know what the deal is with the people who've got Amy. But otherwise this was an entirely forgettable episode.