I wasn't the biggest fan of Kill List or Sightseers – but I could see the black humour in the latter – and I haven't seen Free Fire yet, which looks like Ben Wheatley's most accessible film, so I didn't know quite what to expect from A Field in England. Having now seen it, I still have no idea what it was.

It's the Cromwell era civil war of the 1800s and an officer's cowardly right hand man, a soldier and two deserters banded together by fate decide to run away from the nearby battle instead of back into the fray. There's the vague promise of an inn nearby that keeps them going, but even before things get weird you're sure they're either not going to reach it or that it doesn't exist at all.

They're profane, argumentative, nothing alike and of very different temperaments and you're reminded of that other cast of English oddballs who never belonged together but defined each other (The Goodies) – especially in several moments of laugh out loud humour.

But things do get very, very weird. Not just in the story, but with the way Wheatley decides to tell it using sound and images. In fact the further along it goes, the more it seems like a Timothy Leary-inspired art installation than a movie. In fact if there'd been any story, I'd completely lost the thread of it by halfway through.

They somehow find or dig up or release another man (Michael Smiley) from a grave or well or something – it's the first odd aesthetic choice in that the film doesn't show anything but the four men pulling on a thick rope, and suddenly some other guy has appeared.

He's apparently a deserter or some kind of criminal like they are because the skittish religious one among the band tells him haltingly that he's under arrest and in custody until he can be delivered to authorities (the reason why or what prior history they have is never very clear). But the new guy just smiles and says with measured assurance that they're actually all under his power.

His stated plan is to make them help him find treasure buried somewhere nearby, and in short order the other men are in a deep hole shovelling out dirt while they do so. But what goes on both around that central premise and in the filmmaking style departs from it totally and absolutely. Wheatley uses extreme slo-mo, double exposure, weird musical cues and anything else it seems he could think of to make the whole thing feel like some LSD fever dream.

You wonder if it's all a parable about drugs, Satan or something you can't even see and it all feels more like Wheatley's prowess as a filmmaker than a plot, morphing from Monty Python to David Lynch and my interest in it evaporating completely.