I think this is my favourite episode of this series so far - and a very different premise from normal Who, while still being unmistakably Who. It was full of great little lines, that possibly don't look so good on paper, but the delivery was perfect, for instance "There's something that doesn't make sense, let's go and poke it with a stick!" :) My guess is the film reference was some zombie film (I've not actually watched any zombie films, and I'm extremely unlikely to ever do so, you're likely surprised to read ;) ). And I gather from the internets that there's a Red Dwarf episode that does the no-it's-not-real-after-all thing, too.
And on that note I liked that the thing that was making me all ready to roll my eyes a bit at Doctor Who "science" was in fact the clue that that wasn't the real world either - I didn't actually see that coming at all, though I should've done, it was obvious in retrospect. It was kinda clear from the beginning that the 5-years-later sleepy-village wouldn't be the "real" one, but it was nice that it was the one with the "normal" Doctor Who story to offset that. The alien-infected pensioners were really creepy, right up until the eyes-in-mouths thing, which just didn't work as well.
The Dream Lord on the other hand was very effective the whole way through. Nice fakeout with implying it might be the Master with the line about "no-one hates me as much" and it turning out to be the dark self-hating part of the Doctor himself was perfect. And the final bit where the Doctor briefly sees the Dream Lord looking back from his reflection in the console was creepy too - is it meant as a hint we're not in the real world yet? is it ramming the point home that it's the Doctor? Apparently the actor is the guy who does the voice of Dobby the House Elf in the Harry Potter films - I just looked him up on wikipedia coz I figured he must be a "name", and he does indeed have a whole list of things-he's-been-in.
Another fairy-tale feeling episode, too, definitely a theme for the season. Both the cottage in the village in the country for one reality, and Amy-as-Peter-Pan made explicit in the other one. Poor Rory as she was saying "it can be the day before our wedding for as long as we like!" - she clearly sees marriage as the final thing that makes her "one of the grown-ups" and boring. And poor Rory that she's never told him she loves him, never even really realised it herself till she's willing to risk dying for real rather than have to live the rest of her life without him if that was the real world. And still finds it difficult to bring herself to admit it to him afterwards, even with the Doctor prompting her (and drawing parallels to the Doctor, much? In the inability to admit you care about someone, thinking of the two different season finales when saying goodbye to Rose in the parallel universe in particular where we're clearly meant to draw the inference that he loves her but just can't say it).