I hate skipping two episodes, especially since we meet Cassandra in “The End of the World” and Charles Dickens in “The Unquiet Dead” (not to mention Gwyneth), but we can make up for it by meeting Harriet Jones (yes, Harriet, we know who you are), UNIT, and the Slitheen. The double episode is also a good look at the effect time travel has on the people left behind, which I thought was an interesting way to go; it’s not all exploring worlds, it’s about people, too. Mostly about people, actually; the Doctor is a real people person. Unfortunately, it’s two hours of fart jokes, which I could do without, but it’s still good storytelling. Plus Harriet Jones.
One thing to look at in this story is managing huge casts. I love a large cast of characters to work with, but this story has a lot of speaking parts–the Doctor, Rose, Mickey, Jackie, Harriet Jones, the Slitheen who show up in different bodies, the political aide who should have been wearing a red shirt, UNIT, a platoon of soldiers, the morgue attendant, the pig–and they’re all established pretty well, both visually and by their character actions. I have to confess, I like the smaller cast stories because they feel more intimate (see the two episodes we’re skipping), but I think handling this many characters takes skill, although it does help that the plot is your basic Aliens Here To Take Over the World. Thank God they’re calcium based.