The Belko Experiment, from director Greg McLean and writer-producer James Gunn, is a bloody-good exercise (emphasis on bloody) in human savagery. Yes, it’s an awesome Office Space-meets-Battle Royale mashup, as the posters would indicate, but it’s also somewhat of a disturbing revelation.

In the middle of a desolate strip of land in Bogota, Colombia there stands a nondescript office building where 80 American employees of the non-profit Belko Industries go about their days like the corporate drones they are. Cue the confused looks and increasing tension when the entire place is suddenly sealed and shut out from the outside world. And when an unknown voice takes over the intercom system to tell everyone that they must murder 30 of their own within 2 hours (or else 60 will be dispatched via an “alternate method”), the fear and dread set in, followed by the desperate (and ultraviolent) attempts to stay alive.

The cast is chock-full of familiar faces from the small screen. The perfectly cast Everyguy John Gallagher Jr. and Emerald City‘s Adria Arjona are the company’s own Jim and Pam. Scandal‘s Tony Goldwyn is the take-charge COO who forms an alliance with Belko’s resident alpha dogs, which includes Scrubs‘s John C. McGinley, playing the office meathead misogynist. And everyone else gets some facetime before the shit hits the fan: Melonie Diaz is the office newbie who’s more resourceful than she appears, Silicon Valley‘s Josh Brener is the office nerd, veteran actress Rusty Schwimmer plays the maternal figure of the group, Scream Queens‘s James Earl is the security guard who just wants to do what’s right, and even The Walking Dead‘s Michael Rooker pops up as the building’s custodian, armed with his trusty wrench.

Belko revels in its B-movie bloodshed and twisted antics. Classical music accompanies one unbelievable sequence in which heads literally explode. Office management turns into a mercenary task force. And who knew weaponizing office supplies could be so horrifically fun to watch?

What makes the film work is its crackling energy and ability to maintain a straight face through the over-the-top massacre while the filmmakers wink at the audience through clever details. (“Bringing the world together” is the company’s motto on display in the building’s lobby.) There’s also the intriguing mystery at its core: who’s the unidentified puppet master pulling all of the strings? By the time the curtain is lifted, you may have forgotten that question because you’re still trying to recover from every stabbing, shooting, bludgeoning, axing, and burning you’ve just witnessed.

In the end, McLean and Gunn (yes, Guardians of the Galaxy‘s James Gunn) have crafted a swift horror-satire that subverts expectations (don’t get too attached to anyone) while managing the descent into madness with a balance of gore and natural laughs that keeps you engaged throughout the film’s lean and mean 88-minute runtime.

A grisly, good time.