I loved the episode. I have no nitpicks about any of the retro stuff. Looks great to me.
Only complaint was Clara being from the Victorian era didn't have ANY apprehension about all the oddities going on around her: aliens, snowmen, computers, memory worms, etc. I was confused if that was just her not being easily impressed or if it was supposed to indicate how she's a "future soul" or whatever. I will say, I loved her line about being "smaller on the outside". It was obvious she was going to say that, but it fit her quirky personality perfectly.
But damn, is she fine. Just edges Martha for hottest companion of the new series for me.
Is there a story behind her being cast as the companion? Did they know this when they filmed her initial Dalek Oswin story or did they like her so much they wrote her in?
If they wrote this Oswin is Clara storyline by the seat of their pants just because they liked the actress, I have to say they have thus far done a swell job because its intriguing for sure.