“Is it a trap? Is it a prison? Is it a torture chamber?”
No, it’s the Doctor’s own private hell: an endless loop of an episode, where his only company is either in his mind (Hi Angel Clara!) or trying – somewhat half-heartedly – to kill him.
The design of this admirably ambitious episode owes something to Escher, the theory owes much to The God Complex, and the execution owes everything to the supremely talented Peter Capaldi who has to try to keep the audience engaged via running commentary throughout.
It’s a thankless task, however, as, intricate, clever and profound though the whole thing is – Steven Moffatt certainly knows how to plot a puzzle – it also goes on forever. Which, given the big reveal, is obviously the entire point, but is also deeply frustrating to watch despite Capaldi giving it everything possible. I wanted to like “Heaven Sent” but I got fed up with it very early on and only really started to get interested when the Doctor cracked the mystery – it felt like the episode and I both woke up when the Doctor did, and everything suddenly got a lot more gripping. Which made the last ten minutes or so very good indeed, but the rest of it? A swing and a miss.