When a movie takes its title from a tagline used to promote “Indiana Jones and the Last Crusade,” I can’t help but walk into it with high expectations. Indeed, “Keeping Up with the Joneses” boasts a plot which quickly reminded me of “True Lies” and “Mr. and Mrs. Smith” in which government spies disguise themselves as ordinary suburban residents, and it has a cast of actors who you can always count on to give you a fun time. It’s even directed by the man who gave us “Superbad” and “Adventureland,” Greg Mottola. But while it does have some inspired moments, “Keeping Up with the Joneses” ends up feeling, to put it bluntly, half-assed.

We meet Jeff Gaffney (Zach Galifianakis) who works at a corporate office as a human resources director. He is happily married to Karen (Isla Fisher), and they have two children who, as the movie starts, are heading off to summer camp for a few weeks. For the first time in years, the Gaffneys have the whole house to themselves which has them thinking of all kinds of mischief to get into, but any plans they have for getting naughty are interrupted when a new couple moves into the neighborhood.

Tim and Natalie Jones (Jon Hamm and Gal Gadot) are not your usual couple as they look as if they have traveled all over the world, and they look far too gorgeous to pass as ordinary people. As a result, the Gaffneys get overly suspicious and are eager to learn everything there is to know about them. It doesn’t take long, however, to realize they are spies, but whether they are foreign or domestic spies remains to be seen.

“Keeping Up with the Joneses” gets off to a strong start as we get a picturesque view of suburbia with the peaceful neighborhood these characters inhabit. As the camera pans around the different houses, one of them blows up into smithereens, and the explosion almost feels like something out of a Kathryn Bigelow movie. Next thing you know, the story moves back to two weeks before the explosion, so we already know this peaceful neighborhood won’t be very peaceful for much longer.

The great things about the movie is the cast. Galifianakis gets to play a different role this time around as Jeff Gaffney is not like the mentally unstable characters he became famous for playing like in “The Hangover.” Seeing him play a down to earth guy who is all about family and good times feels like a stretch for him, and it’s fun watching him opposite Hamm especially when they have lunch at an underground restaurant which is definitely not for vegans.

Hamm gets to play on his sexy guy image, and he is well matched with Gadot who looks very comfortable in the action comedy genre. Isla Fisher has been great fun to watch in any movie she appears in ever since her scene-stealing turn in “Wedding Crashers,” and she doesn’t disappoint here. There’s also a nice pair of performances from Matt Walsh and Maribeth Monroe as a pair of neighbors who might be getting a little to nosy in everyone’s affairs.

But as terrific as this cast is, they are not enough to save this movie which runs out of inspiration very quickly. It would have been more fun if the director and screenwriter kept us guessing as to whether the Joneses really were spies or not. Looking back, I kept thinking everyone missed out on various opportunities to make this movie cleverer than it is. This could have been an uproarious comedy had more effort been put into the script. After a while, we know how things are going to turn out for the four main characters here, and it just reminds us of other movies like it which were much, much better.

When the movie reaches its conclusion, it’s sunk by a predictability everyone could have avoided for the benefit of the audience. What we are left with is a premise which everyone could have and should have had a lot more fun with. The characters, despite the best efforts of the actors, could have been better developed to where they don’t feel like caricatures. The action scenes are fun, but you feel like they could have been more thrilling. Instead of accepting the movie for what it is, we keep thinking about the movie it could have been, and realizing this is depressing.

“Keeping Up with the Joneses” is one those films I analyze endlessly as I watch it because I am convinced I could have done a better job with the material. This premise could have been taken in a number of different directions and could have ended up being an insane amount of fun. But we get instead is a motion picture which have spent more time in the development phase because this one came out of the oven far too soon. It has its moments, but it could have had a lot more of them.

* * out of * * * *