Very impressive animation overall, and a pretty solid story.  I like how the 1950s was portrayed pretty honestly - with some time spent on the period's gross flaws around segregation, but also acknowledging these people are human and still care for one another.  Mr. Ring-A-Ding was impressive as a villain in how he looked, but also in how production made him both silly and scary.  I love the scene where he was talking about how learning about perspective is slowing him down as he has to climb what are now giant steps to him - this episode is full of humour and ideas like that and it really works well.  I maybe didn't respond as strongly to this one as others, but I still very much enjoyed it and had a good time.

I like how RTD is still featuring godly characters for the Doctor to go up against.  They are fun villains who add a new dynamic with the Doctor we don't often see.  However, it does feel like RTD has no means of ending these kind of stories in any satisfying way.  The Toymaker, Maestro, and Sutekh all had pretty disappointing endings, and Lux hits that trend hard.  He literally just floats away in space at the end of the story and that's that.  It's a deeply and profoundly lame way to end an otherwise fun and fine story.

Still, along the way we get a lot of good character work with Belinda and 15, which makes a big difference in a positive way.  I really like the scene where our protagonists become a 2D, simple animation, and have to "give themselves depth."  That's some really fun and memorable writing which definitely helps make up for that lame ending.