When a movie is as reasonably entertaining as Due Date, it’s unfortunate when it has an obvious and glaring flaw that nearly sinks the entire endeavor. But Todd Phillip’s Due Date is never more than the sum of its part because of it, and as such it’s more a series of scenes than a film.

Robert Downey Jr. stars as Peter Highman, an expectant father we can tell is somewhat superficial by the opening sequence (there’s a reveal that shows him to be constantly on his phone). He’s heading back home to Los Angeles to be with his wife Sarah (Michelle Monaghan) and – hopefully – Gay Perry (Val Kilmer, sadly SPOILER not in the movie END SPOILER), as she’s about to have a C-section. In to his life comes Ethan Tremblay (Zach Galifianakis), who has a similar bag, and that leads to a frisking at the airport (by RZA) when there’s a marijuana pipe. Of course, this is a road trip movie, so both Ethan and Peter are ejected from the plane in a set piece of comic misunderstanding that dies on screen. This sets the tone for the film: they need to have this scene, but they couldn’t come up with a way to make it work, so it mostly just happens in the dumbest way possible.  

Peter has no wallet or luggage, is put on a no-fly list, and can’t rent a car, so he reluctantly accepts a ride from Ethan. And so they’re on the road from Georgia to Los Angeles with just enough time to get there before Peter’s wife gives birth. But – as to be expected – this is not Two Lane Blacktop as a comedy, and there’s all sorts of side adventures along the way.

The biggest problem with Due Date is this: At no point do you enjoy or want to be in the car with these two guys together. It’s one of those problems that makes me wonder if it was always an issue with the script and because they had three hot talents (Downey Jr., Galifianakis and Phillips) that they figured they could fix it along the way, or if Downey Jr. and Galifianakis lack of chemistry robbed the film of relaxing into the ride. But without the fun of a road trip in the middle of a road trip picture, much like Peter you can’t wait until they get to Los Angeles so the whole thing can end.
There is still the framework of what amounts to the standard narrative. Peter is high strung, and constantly on his phone – suggesting that he’s not ready to deal with the responsibility of a child. And in one of the best moments of the film, he shows how little he’s ready to deal with children as Ethan spends some time buying medical marijuana from Juliette Lewis and the director Todd Phillips in a cameo. Ethan is of course child-like, but at no point does Peter’s or Ethan’s characters go through transformative processes, and so when the film hints as a possible less-than-pleasant resolution for Peter, it’s hard not to feel that that ending would have been way more satisfying.

This may have to do with Galifianakis’s character. He’s playing a slightly more with-it version of his character from The Hangover. Here he likes smoking pot and masturbating, he falls asleep easily, he has a pocket dog, and he loves Two and a Half Men. The latter leads to some funny bits (Ethan has a fansite called “It’s Raining Two and a Half Men”), but the movie has no teeth with these jokes. To give the character heart, he’s got the ashes of his father with him, so that leads to all of the “bonding” moments.  The nice thing about The Hangover is that Bradley Cooper and Ed Helms could look at each other when they found his character annoying, but they obviously felt protective of him. Here, Downey Jr. mostly plays contempt, and you believe it.

But though the film attempts to build some bonding scenes, you never sense that either actor is all that invested in those moments, and they are – of course – undercut by sequences that start with healing, and then there’s a reveal that ruins their current happiness. There’s nothing like the scene in Planes, Trains and Automobiles (the obvious forbearer) where Candy’s character sells the plastic hoops. Instead what you get are a series of small roles from people like Juliette Lewis, Jamie Foxx and Danny McBride. They show up, do a little schtick and leave. You hire a professional like Danny McBride, and he can be hilarious for a good four minute scene, and if you have enough moments from people like him, and the two leads doing enough jokes to distract, the experience isn’t painful.

You can feel the film almost settle into a good rhythm, and nearly save the third act when Ethan accidentally hotboxes Peter, and for the first time relaxes and has a good time. For a couple moments the two actually seem to enjoy each other and you can see what the movie could have been if they were interested in that. But this sequence leads to one of the worst in the film, where they take a wrong street and end up at the border of Mexico, stopped by customs. It’s the end of this sequence that tells you the movie you’re watching: nothing that happens is of any consequence to the characters. The trailers made me think I might hate Galifianakis doing a variation on the role that made him famous, but he’s relatively funny in the role, while Downey Jr. is mostly the straight man (though he does get the biggest laugh in the movie). As a fan of Galifianakis, I’m happy that he’s also on Bored to Death, as his work there shows that he doesn’t just have to play the idiot.

Phillips made a formula picture in putting two people together who hate each other to start with that then become lifelong friends as a result. But formulas are tricky business, and Phillips seems to have no interest in the mechanics – there’s a number of the critical plot sequences that either feel forced or like placeholders. It’s understandable to hate the formula, but for a film like this to work you have to then be a satire of these sorts of movies. Due Date falls right between being a “forced friends” movie and a parody of those films, which is the exact worst place it could end up. And unfortunately, it’s not as successful at doing it as well as Phillips’s Road Trip.