When Quirk Books publisher Jason Rekulak first pitched the idea of injecting a healthy dose of brain-eating gore into one of the most revered novels of the 19th century, not even he could have imagined the mash-up mania he was unleashing on the world. Freely adapted from Jane Austen’s original 1813 novel, Seth Grahame-Smith’s Pride and Prejudice and Zombies spent more than 50 weeks on the NY Times Bestseller List, spawning not only a prequel and a sequel but an entire genre of parody mash-ups like Sense and Sensibility and Sea Monsters, Abraham Lincoln: Vampire Hunter and such recent Quirk smashes as William Shakespeare’s The Empire Striketh Back and The Jedi Doth Return.

So, naturally, it was only a matter of time before Hollywood came calling. And though the Grahame-Smith scripted Abraham Lincoln: Vampire Hunter tanked at the box office in 2012, the pre-release buzz about Prejudice was much more encouraging.

Produced by Oscar-winner Natalie Portman, Prejudice was directed by celebrated indie helmer Burr Steers (Igby Goes Down) and like the novel, promised lush, period costumes, gorgeous locales and fiery, strong-willed Austen-ian heroines kicking serious zombie ass. Also featuring star turns from Downton Abbey’s Lily James and Game of Thrones’ Lena Headey, Prejudice seemed poised to take the literary mash-up phenomenon to the next level on the big screen and then…it didn’t.

Opening in sixth place at the box office on Super Bowl weekend behind such total turkeys as Kung Fu Panda 3, Hail, Caesar! and the latest soppy Nicholas Sparks adaptation The Choice, Prejudice took in just over $5.3 million before limping off into the fog outside Longbourn like one of Grahame-Smith’s “sorry stricken”.

And though I’m never one to equate box office success with quality, as a fan of both zombie lore and Jane Austen, I was prepared to be disappointed with this one. The good news is that Prejudice isn’t nearly as bad as you’ve heard, but it’s also nowhere near as fun and campy as it should be.

Opening with a very cool scene featuring Mr. Darcy (Sam Riley) reimagined as a take-no-prisoners zombie hunter in an English countryside suddenly overrun by the undead, the first third of Prejudice is a pitch-perfect mash-up of period piece drama and awesomely staged zombie horror. Layered over the existing story, the zombie mythology in the film is filled with juicy, class-conscious details – like the fact that the rich send their children to train in the art of zombie warfare in Japan while the children of the lower gentry can only afford training in China – and the period-appropriate weaponry on display is just as gorgeous as the corsets and vintage boots they’re tucked into. There is a visceral, fanboy thrill in watching fetching young lasses in Regency ball gowns slicing zombie heads off with samurai swords.

But sustaining the film’s delicate tonal balancing act proves to be too much for Steers about midway through. And though the cast is more than up to the challenge – particularly former Dr. Who Matt Smith as a highly-annoying Parson Collins and Dark Shadows’ Bella Heathcote as a zombie-slaying Jane Bennett – once Prejudice’s proverbial carriage veers off the country road it never really recovers and the movie becomes very boring very quickly. And by the time Prejudice slogs to its dreary, inevitably disappointing climax, trust me, the elegantly appointed zombies onscreen won’t be the only ones begging for sweet mercy.

Now playing on select British Airways, Virgin Atlantic, China Southern Airlines and United flights worldwide, Pride and Prejudice and Zombies is also available to stream via iTunes, Amazon Video and Google Play.