Now don't get me wrong, the series has always had an iffy grasp of science, what with writers who didn't know the difference between a solar system and a galaxy amongst other things. But it usually tried to act like its science was real. It usually felt as if the writers were told, 'I don't care if you've made it up, it has to be internally consistent and make sense within the world you've built.'
Now there are plenty of examples where this isn't necessarily the case in the original series, but they usually felt like exceptions, rather than the norm.
The magic science in the new series has constantly bugged me. From the sonic screwdriver being able to do literally anything needed, except when the plot demands otherwise, through things like 'let's just mix all the medicines in together, and that'll cure all these people instantly,' 'if I let the weird lightning pass through me it'll change the nature of the dalek hybrids,' and 'all you have to do is believe in fairies... er... Timelords.'
This year's Christmas special has its bit of magic science with the way the planet's native lifeforms get about. There's a quick nonsensical explanation for it, but it doesn't matter. Because in Christmas Carol it works.
And that's the thing, there's actually several elements that shouldn't work, that have quick, hand wavy explanations, and at least one moment that doesn't have an explanation where, by series canon, it really needs one. And none of that matters. The world that's presented allows for all this by feeling internally consistent, and the fantastical elements work because of that.
The story is an enjoyable watch. The characters are mostly well handled, Michael Gambon is having a ball, as is Matt Smith. It's not overly dark, though it has its share of harsh moments and scares, but it's mostly fun, silly, and chock full of joie de vivre.
If I have a criticism it's that Amy and Rory didn't get a lot to do, but at the same time to feature them more heavily would likely have drawn attention away from the people who the tale was really about. Oh, and some of the bad guy's meanness seems a little two dimensional and pointless, but then again, they quickly start to build up his depth, so it doesn't really matter.
All up, I really enjoyed it. And it showed me something, too. That in a story well told and enjoyable enough, I don't care about magic science.