It was a "fast and furious" weekend of unprecedented fury. Fast Five, the fifth installment in the Vin Diesel muscle-car movie franchise, took in a record-shattering $83.6 million at the box office, according to studio estimates. That's 2011's biggest opening to date (out-flying the weekend's second place finisher, Rio, with $39.2 million), the biggest April opening ever, and the best opening ever for its studio, Universal. It's also the must successful opening for the fifth film in any franchise, besting Star Wars: Episode II: Attack of the Clones ($80 million) and the Harry Potter and the Order of the Phoenix ($77 million), both of which opened over 3-day weekends. Why was Fast Five such a runaway success?

1. It's actually a good movie

"The film is pretty terrific, one of the most thoroughly successful real-world action pictures in a long time," and a notable improvement over the franchise's previous installments, says Scott Mendelson in The Huffington Post. Yeah, "everyone dug what they saw," says John Young in Entertainment Weekly; both audiences and critics rated the movie highly.

2. And it has The Rock

The Fast and Furious films have long starred charming Paul Walker and muscle-bound Vin Diesel, but the fifth installment added the equally brawny and personable Dwayne "The Rock" Johnson to the mix, strengthening the bid for box office. "Muscle vs. muscle will sell," says Gitesh Pandya of boxofficeguru.com, as quoted in USA Today.

3. It lured an unusually broad demographic

The PG-13 film attracted a young, ethnically diverse audience, says Young. Over half of the audience was under 25. According to exit polls, just over a third of the audience was Caucasian, just under a third were Hispanic, 19 percent were African-American, and 9 percent Asian.

4. Audiences were stoked for a big, loud summer movie

"Fans clearly wanted to get a jump on a summer action movie season that doesn't officially begin until next weekend," says Gary Susman at Moviefone. HuffPo's Mendelson concurs, pointing out that smaller films have been cluttering the multiplex of late, whetting desire for a big-splash film.

5. The IMAX advantage

The film's big earnings were boosted by higher ticket sales at pricey IMAX theaters, says Susman. "About 10 percent of the weekend total came from the ultra-large screens."