I enjoy these “fish out of water” stories. There’s tons of potential for the Doctor to find himself lost among humans, struggling to fit in and understand their ways, but it’s not something that has been done very often, probably because the Doctor has never before been quite so… alien. I can’t imagine this story working with any previous Doctor like it does with Matt Smith (which is odd, because it’s based on a story written for the tenth Doctor).
With Amy trapped on a malfunctioning Tardis, the Doctor has to team up with his new flatmate Craig, played by James Corden, in a spin on the classic Odd Couple scenario. The Doctor tries to fit in during his stay but gets things hilariously wrong, and Craig gets increasingly irritated by the Doctor muscling in on his life and causing friction with his potential love interest Sophie. The wider plot is really about a monster living in the upstairs flat, but it’s centred around a sweet love story full of frustration as Craig and Sophie repeatedly shy away from their feelings. Whatever opinions you might have about James Corden, he’s perfectly suited to this sort of awkward character.
“Perception filters” play a big role, and the revelation of what’s really upstairs is an excellent twist with a nicely creepy tone. Unfortunately, there’s a lot left unexplained, such as whose ship it was and where it went. Maybe that’s not important, and the ship’s control room does get re-used for the Silence in a later episode, but it’s Steven Moffat’s “mysterious era” where plot threads go annoyingly unresolved for years at a time, so it grates a bit.
Despite the darker implication of an alien computer frazzling humans in an attempt to find a suitable pilot, the episode is otherwise lighthearted and comedic. Matt Smith is great as, basically, a total weirdo (sorry Matt) and the writing is funny throughout… however, it does border on the wacky for wackiness’s sake at times, with the Doctor’s crazy spinning machine thing and imparting information through psychic headbutts. That was too silly for me and not really needed, particularly when the story has something more meaningful to say about boring ordinary lives and not falling into a rut. It also shows the Doctor is more perceptive than he seems, as he correctly identifies the romantic desire between his new friends, suggesting his wacky routine is more of an act than a nature.