The highly anticipated Avatar: The Way of Water took in $134 million at the US box office, giving director James Cameron his first $100 million opening weekend — despite falling short of analyst predictions.

Although notching the second highest world-wide opening this year didn't quite match expectations, the film's ultimate success will depend on its long term appeal, a notable attribute of many of Cameron's movies. Avatar: The Way of Water has so far earned $435 million at the global box office.

Though Cameron hasn't revealed exactly how much it cost to make the Avatar sequel, one answer isn't in doubt: a lot. Or in Cameron's own words to GQ Magazine, very f***ing expensive. The star director estimated to industry executives that in order to break even the movie has to be the third or fourth highest-grossing film in history.

That means it needs to make more than $2 billion. Earning nearly $3 billion, Avatar is the highest-grossing film of all time. And only one film during the pandemic era, Spider-Man: No Way Home, has even come close to that mark, raking in nearly $1.9 billion.

But for Cameron it's all about the marathon, not the sprint.

The future of the Pandora isn't going to be determined this weekend, Comscore senior media analyst Paul Dergarabedian said. It's going to be determined over the next many weeks as the film plays, and we'll have, I think, strong week after week numbers.

The film might also be at the top of the list for viewers over the busy holiday period, which also won't include any major blockbuster competition, Dergarabedian noted. However, the movie's running time, 190 minutes, reduces the number of daily showings for theaters.

The film could be a turning point for the movie theater industry too, which had been decimated by the onset of the Covid-19 pandemic. The film's success will also depend on whether audiences will pay for the immersive 3D experience, which has decreased in popularity over time, along with dwindling ticket sales.

In 2009, Avatar earned $77 million in its opening weekend and collected 80% of its gross from 3D showings. That film revolutionized 3D viewing — and for its sequel, premium formats such as IMAX and 3D accounted for 62% of the domestic box office haul.

The Way of Water notched the second highest all-time IMAX global opening weekend and the biggest IMAX December global opening ever.

I think people are on the fence about 3D, Dergarabedian said. But with 'Avatar: The Way of Water' the 3D part of it is as woven in to its appeal as the movie itself.

Disney has placed a huge bet on the Avatar series. The Way of Water is one of four planned sequels, with a third installment set for release on December 20, 2024. The stars from the first film, Sam Worthington and Zoe Saldana, returned as Jake and Neytiri. In the sequel, they live on Pandora with their family.

-- CNN's Oliver Darcy contributed to this report.