After the season 1 finale and last year's Christmas special, my expectations for this were not too high, but after seeing the concept and that it was a Moffat episode, I was cautiously optimistic. I'm happy to say that that optimism was warranted, this was probably one of my favourite Christmas specials of all time, I loved the idea, the execution (for the most part), and the character work, the year the Doctor spent on earth (reminiscent of The Power Of Three) being the highlight for me. As someone who loves to see the Doctor's complex relationship with time in this manner, I really thought that this was one of the best character moments of the Gatwa era so far, and I'm really hoping that the rest of the era follows suit stylistically. There were some parts of the episode that didn't quite land for me, like the slightly ropey CGI of Joy at the end and some of the ways the plot moved forwards, but overall I would say that this is a great, festive, timey wimey story.