Few things have caught the public imagination in recent years quite like the concept of Barbenheimer. When Warner Bros scheduled the release of Barbie to run in direct opposition to that of Oppenheimer, directed by embittered former employee Christopher Nolan, the natural response was to pick a side. Both films were so diametrically opposed, after all, that the competition took on a slightly tribal air. Just who do you stand for? Drama or comedy? Joy or fear? Female empowerment or the death of tens of thousands of Japanese civilians?

But then something bizarre happened. Instead of picking just one film, people started latching on to the idea of seeing Barbie and Oppenheimer together, on the same day, as part of a wildly incongruous double bill. Tom Cruise said he was going to do it. Greta Gerwig posed with tickets to both. Despite spending the last few weeks looking palpably baffled by having to play 400 tinpot YouTube parlour games just to promote his movie, Christopher Nolan also seemed fairly into the idea as well. A rising tide lifts all boats, after all.

But is it a good idea to smoosh two violently different films into a single five-hour marathon? Both Barbie and Oppenheimer came out this week, and I spent an afternoon doing exactly that. The question is, will Barbenheimer save all of cinema as we know it?

In a word: no. In slightly more words: Jesus Christ no, absolutely not, what a terrible, terrible idea this is. Reader, do not attempt Barbenheimer. Or at least, if you do decide to do Barbenheimer, please don’t do it in the order I went to see it. If you take anything from this, it’s that you should really go and see Barbie first. Because otherwise, and I’m talking from very recent first-hand experience, the effect is a little like having your mother’s funeral invaded by a flashmob of parking circus clowns. Which, you know, isn’t exactly ideal.

Because here’s what I just learned. Oppenheimer is a three-hour onslaught in which – and this has been reported in the press, but nevertheless might still qualify as a minor spoiler – the film’s director literally hired his own daughter to have the skin flayed off her face as a graphic demonstration of the immediate effects of a nuclear detonation. What I’m trying to say is that it is a lot.

It’s the sort of film that requires processing. After watching it, you’ll want to discuss it with the people you saw it with. Or you’ll want to read up on J Robert Oppenheimer in greater depth, to better understand the man’s motivations. Or – as I did – maybe you just felt like taking three or four hours to blankly stare into the middle distance, silently rocking backwards and forwards in a state of numb despair at the destructive idiocy of mankind. In other words, it takes a minute.

But oh no, instead you’ll have just enough time to empty your bladder, turn around and subject yourself to the fluorescent full-beam positivity of Barbie. It’s such a tonal handbrake turn that you’ll end up with whiplash, even when Barbie reveals its slightly darker true intentions after about 20 minutes.

And by the way, don’t expect to encounter a lot of fellow Barbenheimers either. On the basis of my visit, people are still firmly intent on seeing either one or the other. Oppenheimer had an older, silently reverent crowd. Barbie, on the other hand, was populated by dozens of children whose parents didn’t get the memo that the film was a self-aware commentary on the nature of feminism and not a fun movie about a toy, and who had to keep asking them what a gynaecologist was.

The cinema, too, felt tribal in a weirdly one-sided way, too. All the staff at my local multiplex were wearing pink. The guy standing next to me at the cinema urinal was wearing a Barbie T-shirt. Oppenheimer, however, was less well represented. Nobody was wearing a mid-century suit, or came dressed as someone who had been physically and spiritually hollowed out by constant nightmarish visions of mass death, which seemed like a missed opportunity.

There certainly wasn’t a lot of crossover, in that I couldn’t see anyone else quivering with blank incomprehension at the indiscriminate violence of nuclear warfare as the curtain went up on Barbie. Or maybe they had all decided to see Oppenheimer second. I don’t know.

That said, would that choice have been much better? After all, who would want to follow up a feelgood comedy about the messy complexity of human life with a bleak meditation on genocide? Probably nobody.

So here’s my advice. Go and see Barbie. Go and see Oppenheimer. But for the love of all that is holy, please do the sensible thing and see them on different days. Honestly, your nervous system will thank you.