I felt that this episode was enjoyable and largely very funny, good qualities for a stand-alone Christmas special to have. I felt that the plot was really interesting and nicely done. It was clever and interesting yet simple enough to follow.

However, while I love the amount of time given over to the timey-wimey plot, I feel that the episode may have benefited from spending some more time on Joy. I feel that, as is, some of the emotional elements were a little shallow and that some more time to develop the character may have really helped this to stand out a bit more. The issue is that I think the time given to the plot was perfect, so I'm ultimately not really sure how I would concretely change anything to improve this aspect for me.

In other areas, the music was nice but nothing really stood out to me as particularly memorable. The set design, costumes, prosthetics and CGI were as great as they've always been this era.

In summary, I found this to be an enjoyable one-off episode that gave me some good laughs.