[Warning: spoilers abound]

Let's Kill Hitler was the first Doctor Who episode after the recent summer break. I thought it wasn't very good. I know, shocking news right? An episode of Doctor Who that wasn't very good - such a thing has literally never happened. At least not since The Almost People, way back in May 2011.

But the thing is, this wasn't one of those filler episodes that everyone must have known was inevitably going to be a bit shit even when they were making it. And it wasn't one of those disappointingly overwrought series finales. This was an episode that was self-consciously an Event that was going to be Awesome. It was, after all, by Steven Moffat, he who can do no wrong.

The thing is: I really like Steven Moffat. I think he's done some of the best episodes since the show was revived, and his last series as showrunner was very good indeed. I'm looking forward to the finale of this series. That said, I've never been happy with the idea that it was shit while Russell T. Davies was in charge, and instantly good afterwards. And Let's Kill Hitler rather neatly showcased his various potential shortcomings all in one go.

In this episode, the Doctor and his companions travel back to Nazi Germany. A new companion who has just been introduced turns out to be recurring character River Song, who turns out to now want to kill the Doctor, and then suddenly turns out not to want to kill the Doctor, oh and by the way when Timelords or quasi-Timelords (don't ask) regenerate they can give up their power to cure poison.

From the very get-go, the episode announces that it is going to be a Rollercoaster Ride of Awesomeness. There is a woman! With a gun and a fast car! And she wants them to go back and kill Hitler! And then there's a robot! With people inside! And Hitler! And OMG she's regenerating! And OMG she's a kick-ass heroine who likes guns AND clothes! And OMG it's a complex flashback replaying the events we've just seen from a new angle to show us just how clever the Doctor, River Song and Steven Moffat are!

So what could possibly go wrong? Well, you might be able to guess from the way I've summarised it. The effect is rather like Michael Bay's famous technique of "fucking the frame" - there's simply an overload of showy stuff going on. The viewer is flung from one Awesome moment to another, with frequent abrupt shifts of direction. Amy and Rory's new friend Mel is introduced out of nowhere, and we've barely rattled through a quick character summary before PAM!! she regenerates into River Song. River Song in turn suddenly turns out to be evil!! until, all of a sudden, she isn't!!

The problem isn't just that it's confusing (though it is, even if you've been following the series diligently). It also becomes rather hard to care about what's happening - it's an intellectual exercise trying to figure out what the fuck is going on, and a spectator sport of witnessing one Awesome one-liner and cool moment after another.

The emotional impact is supposed to come from extremely self-referential, fanboy-ish moments. Instead of scenes in which we are made to feel that anything is at stake or that there is any rapport between characters, we get scenes that we're just meant to care about because "OMG! It's the moment when the Doctor and River Song first get close!" or "OMG! He gave her the diary!" In place of Davies' slides into sentimentality, we get scenes where all emotional significance has to be deduced by reference to other episodes. Both are equally lazy writing.

In other places, Moffat tries to shock us into feeling something. We witness the Doctor writhing in agony as he dies from poison, or River Song screaming as she is tortured by a ray-gun. It's frankly just unpleasant to watch - a case of making things "dark" as a lazy substitute for adding depth (I kind of felt the same about the "Doctor always lies" line).

Then there's the rather stale old attitudes lurking beneath all the oh-so-clever wisecracking and trickiness. Of course there's an oh-so-funny off-handed reference to the Holocaust ("I was on my way to this gay gypsy bar mitzvah for the disabled when I suddenly thought, 'Gosh, the Third Reich's a bit rubbish, I think I'll kill The Fuhrer'") because flippant remarks about Nazis are edgy. Edgy like 'Allo 'Allo. And of course the episode makes sure we know how that River Song is a worse criminal than Hitler, because the most appropriate way to demonstrate the Awesome Evilness of a piece of villainy on a semi-serious sci-fi TV show is to compare it to real-world atrocities.

I'm not even going to get started on the sexism, except to say that it seemed egregious enough this episode to bother me even after sitting through five seasons of the Doctor being hero-worshipped by a string of young female companions (check out Tiger Beatdown instead for discussion on this by someone more qualified to comment than me). But I must say I did roll my eyes at the hilarious bit where it turned out Amy always thought Rory was gay. It felt like the kind of thing that might have seemed incredibly funny in a trendy 90s sitcom that has dated badly.

Now, I wouldn't go so far as to say this episode has revised my opinion of Moffat. He's done many, many great episodes, including as showrunner, and come up with many ingenious villains and storytelling devices. It's perhaps just unfortunate that this particular episode brings to the fore all at once so many of the different elements that are problematic or nearly problematic in his other episodes. I hope that for the rest of the series, he will have reined in his worse tendencies so that we can be treated to a conclusion worthy of this season's opener. But for anyone who thinks Moffat is flawless, I would point to this episode as an example of how and where he can go wrong.