The good part first: watching Deepwater Horizon gave me a feeling I haven't had in a very, very long time. That is, the experience of watching a special effects sequence so impressive in conception and execution that it genuinely seems like something we've never seen before. 23 years after Jurassic Park, CGI has evolved from a radical new way of crafting movies to an annoying, ugly commonplace, but turns out there's some life in it yet, and the exploding offshore oil rig that dominates the film's second half is a seamless blend of practical and digital effects serving to create a profoundly tangible inferno, with jagged metal and heaving spurts of hot flame that seem truly dangerous and physically authentic beyond anything I can think of for literally years. Obviously, it was ridiculous of Lionsgate to spend as much money as they did - $156 million, it's said, so we know the real figure is higher - and how in the hell a fact-based disaster movie in 2016 with no bigger stars than Mark Wahlberg and Kurt Russell was ever going to make back even a sizable chunk of that budget is beyond me. But I'm glad they spent it: the movie has production values miles beyond anything the studio has ever made, production values of the sort that the old super-producers in the '60s used to play at.

The bad part next: Deepwater Horizon also has a first half, and it's crap. This is as straightforward a disaster movie as they come: first we meet the characters and the world they inhabit, with plenty of foreshadowing about how easy it would be for all of this technology to go kerflooey in a violent way, and then that happens, as has been promised by ominous cutaway shots to something that we don't quite understand bubbling in a way that it clearly shouldn't be. In fact, the screenplay - by Matthew Michael Carnahan and Matthew Sand - is so straightforward that it doesn't even bother with the other usual ingredient in disaster movies, the litany of personal dramas so that we feel for the characters when things start to go wrong: one character has a wife and daughter, one has a car that doesn't start properly, and that is all of it.

This proves... well, I guess it doesn't prove fatal, since one of the problems with disaster movies is their idiotic ginned-up character drama, and it's kind of neat to see one of them dispense with all of that. But it's still a bad choice. Because all of that time has to be filled with something, and Carnahan and Sand fill it with mechanisms. Simply put, Deepwater Horizon is obsessed with all the dials and widgets and monitors and systems and failsafes that make an offshore oil rig go. And so we watch in great deal as the men of the Deepwater Horizon mill about the rig complaining about things going wrong, the awful BP executives making sure that the things going wrong aren't likely to get fixed, and spouting off about all of the machines and hardware they're fighting with. I will say this for the writers: they did their research, as far as I can tell. They do not, however, show their work. We have no such stock disaster movie character as the civilian reporter or the new recruit to walk us around and learn about all of these things; we only have a bunch of men and a few women who've been doing this for months or years and have absolutely no need to clarify to each other what in the good Lord's name they're talking about.

The result is what feels like hours, subjectively, of aimless conversations about aspects of Deepwater Horizon's engineering which feel like a novel being serialised in Offshore Oil Rig Monthly rather than something aimed at regular people who don't know jack about any of this. I caught myself wishing, throughout this long, long pre-disaster period that the film had been directed by somebody else with a love of working class heroes in action movies. James Cameron deals with this problem by giving his ensemble brightly-etched archetypal personalities. Michael Bay deals with this problem (poorly, admittedly) by using a razzle-dazzle aesthetic and plenty of music. Instead of Cameron or Bay, we've got Peter Berg here, and he deals with it by making a Peter Berg movie: good and slow pacing, lean hard on realism in the acting style and the acting, and throw a few sotto voce asides about faith, tradition, family, and that sort of thing to the Republicans who make up his target audience. None of this is enough to make the film interesting or even essentially comprehensible, for longish passages.

Even when it is comprehensible, mind, it's still not terribly interesting. The story is an embellishment on the April, 2010 explosion of the Deepwater Horizon in the Gulf of Mexico, which lead to the worst oil spill in history and the loss of eleven lives, an event that was largely the result of corporate malfeasance and shady cost-cutting measures. There's really not a lot to hang a plot on there - basically, the whole thing is a matter of under-maintained machines failing - and what little plot can be dredged up is a matter of the thoroughly venal BP men Donald Vidrine (John Malkovich) and Bob Kaluza (Brad Leland) demanding that everybody act against their better judgment. Which is trite, in the first place, and impossible to take seriously, given that Malkovich - an enormously talented actor who is still mortal and thus capable of errors in judgment - plays Vidrine as half James Carville, half Satan, and sports a cartoon Cajun accent that's most of the way towards qualifying as a hate crime against Louisiana.

When he's not onscreen (which is most of the time), we're just stuck watching Russell, as the rig's commander, fume with fatherly worry (which he does extremely well) and watching Wahlberg, as a high-level engineer, rant and snap and generally be all Mark Wahlbergian. Eventually, things go to hell, and the movie is absolutely and in every way exciting; but is it too little, too late? The action is greatly rousing, though I think Berg miscalculates in trying to force it to be a story of Great American Heroism, With Flags Whipping in the Heat and Wind Dramatically and All. It's at its best when it confronts the pain and horror of being a human in that situation, bleeding and battered and terrified - when it's about raw survival and nothing more. Set against the terrifying hellscape of the burning rig, that movie is more than satisfactory, edited with just enough messiness to suggest the chaos of the event, jumping between little moments centered on several different crew members to give us a sense of what's going on everywhere while pointedly denying us a chance to get a complete view of the whole disaster. It works, at times very well - but it all feels a bit empty, a tribute to some vague thing called "oil rig workers" rather than specific human beings with definite lives, and even its strongest aspects are never more than those of the generically effective summertime blockbuster. And that's not a great look outside of the summertime.