Usual deal for the second half of a two-parter: only stuff not mentioned in the first half gets in.
The End of the World: Companion, freaked out by recent experiences, rings Mum through time and/or space, and gets a kind of bizarre reassurance from it.
The Unquiet Dead: Guest character does heroic self-sacrifice bit, which incidentally also involves self-immolation.
Aliens of London/WW3: How is UNIT's computer security still so rubbish that Martha can hack the nuclear grid using her Ipod Touch? Plus another resolution to the general effect that with one thing changed, everything is now absolutely wonderful. Plus real BBC personalities slumming it in guest cameos.
The Empty Child: "Are you my mummy," indeed.
The Parting of the Ways: The Doctor can't just slaughter the bad guys, he has to give them the chance to back down. Companion, trapped on another planet to the Doctor through Tardis displacement, has to figure out how to get back to him.
The Age of Steel: Doctor instructing companion secretly in what they have to do, using a mobile phone and a video broadcast.
Fear Her, Army of Ghosts and The Sound of Drums: Celeb newsreader guest cameo.
Doomsday: Action grinding to a halt for various people to talk through their issues with each other.
42: More mobile phone and stranded companion antics.
Torchwood: The clone-Martha's relationship with her original, and her death, are lifted straight out of "They Keep Killing Suzie."
The Sarah Jane Adventures: Evil factories with attractive products run by aliens who want to breed; annoying parents who get in the way but sometimes come through for you.
They're still recycling within their own season: As if the other "Partners In Crime" parallels weren't enough, now we learn that the Sontarans want to breed.
Catchphrasewatch: A hat-trick this week: "Bwilliant," "I'm so sorry," and "No, no, no".
Old Skool Who: The Claws of Axos (new technology that is marketed as the solution to one of Earths' major problems turns out to be terraforming devices from an alien species). The Auton Invasion (killer dolls and chairs, meet killer cars). Invasion again (evil genius who recants and does good, plus huge set-piece UNIT battle with expensive hardware); Battlefield (UNIT's arsenal of cool bullets and anti-alien gadgets); Invasion of the Dinosaurs (tracksuited group of Utopians, convinced, wrongly, that they're going to go to another planet to start again). The Android Invasion (gratuitous explanation for lack of Brigadier Lethbridge-Stuart). The Green Death (ending in which the ecosystem will be, by implication, miraculously saved through everyone going green, and companion informs Doctor that marriage to a scientist is more exciting than going around with him).
Everything Else: Bizarrely, the original Japanese version of Godzilla has an equally stupid scientific resolution, in which the monster is killed by some chemical which acts on the sea, but with no explanation as to how they avoid killing all fish everywhere in the world at the same time. Buffy the Vampire Slayer (if you locked Rattigan in a cupboard with Warren from Season Six, which one would win?). Predator ("This isn't war, this is sport!"). Harry Potter (secret academies, with bitter and twisted misunderstood geniuses determined to kill off the unlike).