I mentioned in my review of 'The End of the World' that I can sometimes find Russel T. Davies' jokes to be rather grating. Some of his jokes land and he absolutely does make me laugh at times. But, like 80% of the jokes in this episode are just 'look, fat people farting'. Considering how funny this episode seems to think this is, and how often it makes the joke, I think this is probably the most annoying attempt at humour in the entire history of the show.

There's some good in this episode. I like the reveal of Rose being missing for a 12 months and not 12 hours. I like her reconnecting with her Mum and Mickey, whilst having to account for the extreme nature of her vanishing (and it's consequences). I even kinda like the mystery as it plays out. The crashed ship, the pig "alien", the reveal that all of this was just to bring all of the alien experts (including the Doctor) together so that they can be killed before they can work out what's going on or find a solution. As it unfolds each revelation is intriguing until the last one.

Because, despite the mystery being somewhat engaging for the runtime, the climax is surprising dull. Ending a two-parter with all of our main characters about to die and the reveal of new, scary, alien monsters should be thrilling. But the new, scary, alien monsters aren't actually scary. Part of this is that they've mostly been making bad jokes for a lot of the episode, part of this is the design doesn't do much for me, and part of this is that the climax drags on for ages (with a very timid score which does absolutely to build tension). We cut between Rose & Harriet, Jackie and the Doctor all about to die for so long without anything happening, that the Slitheen just feel less and less threatening. I'm less worried that these characters are about to die, because I've just watched the villains stand around not killing them for 30 seconds.

It all ends very tamely, when it should be thrilling. It should make me want to watch the next installment, but the villains are so weak that I want to skip it. This episode should do a lot of things better than it does. The first proper dud since the Revival of Doctor Who.