Legendary Entertainment's much-anticipated period monster epic The Great Wall opens across China on Friday — and the whole industry will be watching to see how the unprecedented fusion project pans out.

With an estimated budget north of $150 million, the film is the biggest Hollywood-China co-production ever, designed to bridge the world's two largest box office territories. 

The Great Wall is directed by Chinese maestro Zhang Yimou (Red SorghumHero, House of Flying Daggers) — his first picture in English — and stars Matt Damon, Willem Defoe and Pablo Pascal, along with a phalanx of A-list Chinese talent, including Hong Kong's Andy Lau, local heartthrobs Lu Han and Lin Gengxin, and half a dozen others.

The film tells an inventive origin story about the world-famous cultural artifact of its title — that China's Great Wall was built to defend against a far greater threat than warring nomads from the North. Damon plays a British mercenary who joins the Chinese to fight for humanity against an army of Taotie — monsters symbolizing greed from ancient Chinese mythology — who wage an attack every 60 years.

Co-produced by Legendary, Le Vision Pictures, China Film Group and Universal Pictures, the film opens in North America on Feb. 17.

From potential casting scandals to box office slowdowns to high-stakes corporate buyouts, here are five reasons why the The Great Wall offers both big risk and major potential upside to all involved.

A Monumental Test Case

The Great Wall fits into a potentially lucrative mold that few big films actually have managed to make successful. The film was developed as a U.S.-China co-production — and it has received that difficult-to-land designation from Chinese regulators.

Official co-pros are entitled to better revenue-sharing terms than imported films usually receive in China — 43 percent of after-tax ticket sales, instead of the usual 25 percent. In exchange, they must feature large numbers of Chinese cast, employ high-level Chinese production crew, shoot in the country and tell a story involving Chinese cultural elements.

Given that North America and China are the largest movie distribution territories in the world, jumping through these hoops makes a lot of sense on paper, but studios have found it daunting to meet the model's demands, while telling a story that straddles disparate cultures and still works well enough to succeed on a global basis. Tentpoles like Iron Man 3 and Transformers 4 entertained the idea of pursuing co-production status before scrapping the idea because of the depth of Chinese culture the movies would need to include to qualify. The Forbidden Kingdom — from 2008 — was one of the last big U.S. films to get China co-production status.

All of which is to say, the whole industry is watching to see if Legendary and Le Vision can make it work. If the film does big business in both middle America and the Middle Kingdom, expect more such fusions to be greenlit — if it bombs in either market, while doing tepid business in other territories overseas, big budget co-pros will continue to inspire trepidation. 

A Potential Race Scandal

It's safe to assume The Great Wall's first trailer didn't elicit the response Legendary was hoping for. Shortly after it dropped in July, some critics suggested that Damon's casting in the lead amounted to another case of "whitewashing," whereby white actors are chosen for roles that should have gone to actors from other ethnicities. In a widely shared tweet, Taiwanese-American actress Constance Wu, star of ABC's Fresh Off the Boat, wrote, "We have to stop perpetuating the racist myth that [only a] white man can save the world."

Damon has argued otherwise, saying that his character "was always intended to be European," and emphasizing the collaborative nature of the project, which intends to meld Hollywood and Chinese star power. "That whole idea of whitewashing, I take that very seriously," he said during a press conference in Beijing.

Of course, no one has seen the full film yet. If Damon's character and performance go down well with Chinese fans, his star could burn even brighter in the world's most populous nation, where he's already a favorite thanks to The Martian and the Bourne franchise — both local hits. If it turns out there is some merit to the white-washing characterization, he could find himself the target of more uncomfortable media attention. It's hard to remember a riskier role for the amiable actor.

A Symbolic Release for China's Richest Man

The Great Wall is the largest important release to date for Legendary East, the China subsidiary of Burbank-based Legendary Entertainment, which Chinese billionaire Wang Jianlin’s Dalian Wanda Group bought earlier this year for $3.5 billion. Wanda, which also owns the world's largest collection of cinema chains, including North America's AMC Entertainment, is understood to have bought Legendary in the interest of acquiring Hollywood-level production prowess — and also to get a piece of the international box office, where Chinese films have typically foundered, no matter how big their success in the home market (Stephen Chow's The Mermaid made $526 million in China and about $25 million everywhere else).

Legendary's first tentpole release after the buyout was Warcraft, which earned a huge $223 million in China, while flopping in North America ($47 million) and making minimal impact internationally — a performance, ironically, rather similar to the typical Chinese blockbuster.

Wanda and Legendary are leaving little to chance in China for Great Wall, having mounted a massive local marketing campaign involving dozens of promotional partners. But should the movie again disappoint overseas, it stands to question whether Legendary really is helping Wanda achieve its international goals. Some also have argued that Legendary has been more successful as a financier of other people's movies, such as Warner Bros.' The Dark Knight or Universal's Jurassic World, than it has been as a developer and producer of its own (notable flops from the studio include 2015's Blackhat, Seventh Son and Crimson Peak). Again, The Great Wall could be perceived as a test case.

The Master Needs a Hit

Zhang Yimou is a pillar of the Chinese film industry. Considered a key member of China's Fifth Generation of filmmakers, his early work — Red Sorghum (1987), To Live (1994) and Hero (2002) — won him a Berlinale Golden Bear, Cannes Grand Jury Prize and Oscar nomination, respectively. He also directed the unforgettably grand opening ceremony for the 2008 Beijing Olympics.

But he's now in need of another win. His last big international success, House of Flying Daggers, came out in 2004; and his most recent release, Coming Home (2014), was critically lauded but did middling business in China. And the last time he attempted to direct an A-list Hollywood star — Christian Bale in the WWII drama Flowers of War, opposite Chinese actress Ni Ni — the results were critically and commercially execrable. The outcome of The Great Wall could determine whether he's handed another $100 million-plus international budget anytime soon.

Bright Spot Amidst a Slowdown?

Even more so than Zhang, the Chinese box office is hungry for a blockbuster. In the first half of 2016, box office growth slowed to 21 percent in China. That number would be considered miraculous in North America (box office grew 6.3 percent in 2015, in what was considered a huge, Star Wars-boosted year), but in China it represented an alarming deceleration from the astonishing 48 percent growth rate of 2015. In the second half of the year, things have gotten worse: The box office shrunk in September, October and November, and the industry is now flirting with he possibility of its first full-year decline in almost a decade. Industry watchers blame myriad factors — a crackdown on box office fraud, a decline in subsidies from hugely popular mobile ticketing services, changing demographics, and much else. But the most immediate cause has been a lack of high-quality local tentpoles worthy of becoming event movies. True to its title, The Great Wall represents 2016's last hope of warding off a dire outcome.