I have followed James Gunn‘s career from the beginning, and generally speaking, I have loved it.

I saw Tromeo and Juliet in the theater, when it came out. Shortly thereafter, his novel The Toy Collector was released and I reviewed it for a major publication. When he costarred in and cowrote The Specials, I was quoted on the DVD. His Scooby-Doo scripts were fun updates, his Dawn of the Dead remake should have been sacrilege but wasn’t, and when he finally got to direct, Slither and Super were worth the wait. It’s still mind-blowing that Marvel let him make two movies reflecting his uniquely twisted comic sensibility.

You see that there’s a “but” coming here, right? And this is it: The Belko Experiment is my least favorite movie James Gunn has written.

Not that it utterly sucks, or anything–Gunn is a skilled enough writer that even when he’s coasting, you’ll get a competent screenplay. But while the words and structure may be intact, the inspiration isn’t. Belko is an office-set mash-up of Saw and Battle Royale, and little more. The direction, by Greg McLean (the Wolf Creek movies and TV pilot), is an equal comedown: functional, extremely basic, and still feeling like a first draft in search of a spark.

The Belko building is at least a surrealistic and amusing setting: a generic American mini-skyscraper surrounded by the farmlands of Bogota, Colombia. The company supposedly assists with the relocation of American workers to firms outside the U.S., but it might as well be typing TPS reports; what they actually do mostly looks like unimportant busy work. And on one particular day, there is a surprising amount of extra, military-grade security, searching all cars and sending home every local Colombian employee, leaving only the North American imports to wonder what’s going on.

Gunn’s shorthand banter to reveal character is strongest at the beginning, giving the characters weird little quirks we’ll remember (one guy has an ant farm, another collects toy biplanes) that would pay off later in any other movie, but here just serve as casual throwaways. Among them, though, he drops the seeds of the first big rivalry to come: office creeper Wendell (John C. McGinley, presumably cast in part for the Office Space connection) keeps harassing beautiful, smart Leandra (Adria Arjona), who’s already part of a couple with our obvious protagonist-to-be, Mike Milch (John Gallagher Jr.). It’s one of several instances of tension that rise when the building is suddenly put on full lockdown by exterior shutters that are basically adamantium, and a voice on a hidden PA system instructs the employees to kill a portion of their coworkers, lest they all be killed by whatever mysterious force is watching them. At first only two bodies are called for, but it escalates quickly.

Because the audience’s point of view is confined to the building, and escape soon becomes clearly impossible, there aren’t many ways the plot can really deal with the mysteries of why and how this is happening; had even one of the Colombians sent home become suspicious and started investigating, those questions could have driven a parallel narrative, as in the first Saw movie. There are some answers at the very end, but presenting them earlier could also have given Belko more of a satirical edge, like Battle Royale, where we know exactly why this punishment is being delivered, and by whom, and how flawed the logic behind it is. Instead, this film dwells only on the killings and the ensuing splatters of blood over white office walls. Nothing particularly wrong with that, but if you were hoping for creative kills, at least, you may be disappointed to know that a large proportion are simply done by people shooting each other with guns.

The threat of constant death is enough to keep any horror hound’s attention. If this had been made in 10 days on a budget of $100,000, it might impress a lot more; Gunn wrote the script in two weeks, years ago, and it shows. McLean, whose work is usually more atmospheric, uses very basic shots and doesn’t feel like he gave the actors a lot of direction. When you see a take of Michael Rooker, for example, looking terrified in an unconvincing way, you may wonder why he wasn’t offered a chance to do it one more time. And he’s far from the only one.

Tony Goldwyn, who will probably become part of Gunn’s regular stable of actors after this, impresses the most as the office boss, Barry Norris. When the first hint of danger hits, he’s all alpha-male assurances, patting people on the shoulders and generally playing the affable big brother. The moment the stakes go up, however, he instantly and convincingly flips to ruthless military mode, taking it upon himself to decide who must live and die, because who better than him to take on such a “burden” (that obviously includes saving his own skin)? On the opposite end of the warrior spectrum is office stoner Marty (Sean Gunn), who insists until he’s blood-red in the face that this is all just an illusion.

The problem with The Belko Experiment is that it’s uninspired. Even the music choices reflect that: opera overscores a silent montage of tragic deaths, while Spanish versions of “I Will Survive” and “California Dreamin'” are offered up as if they were Advanced Satire, rather than Basic Irony 101. Milton setting the Initech building on fire was a more entertaining bit of workplace vandalism than anything going down at Belko.

There could have been more here if more time had been taken to really focus on what the filmmakers wanted to say. If they do a sequel, it needs to utter more, metaphorically, than “exploding heads are cool.”

Rating: 2 bloody burritos out of 5.

Images: Orion Pictures

Luke Y. Thompson is Nerdist’s weekend editor and a member of the L.A. Film Critics Association. He Tweets @LYTrules.