Justin Bieber wasn’t mincing words. “I’m here to bring you the 18 to 24 demographic,’’ the teen pop star told Billy Crystal in the opening Oscar montage. “So, how long do you want me to stay here for?’’

The two were spoofing “Midnight in Paris,’’ a film about time travel, and actually it did feel like Bieber had swooped in from the future. Because everything else about this year’s Oscars had a distinct vintage feel, from the honored films harking back to early years of cinema, to the longevity of some of the winners, to Crystal himself, hosting for the ninth time.

Did the Return of Crystal achieve its purpose? The reviews were mixed, with some loving his familiar zingers, others feeling they were more than stale.

But Crystal can claim a victory for the over-60 set: The Nielsen Co. estimated Monday that 39.3 million people watched the Oscars on ABC Sunday night, up from the 37.9 million viewers during the much-panned 2011 show where the much younger James Franco and Anne Hathaway shared hosting duties.

Much has been made of the retro feel that characterized the two most-honored films: Best picture-winner “The Artist,’’ a black-and-white, mostly silent paean to old Hollywood (it also took best director and actor), and “Hugo,’’ an equally loving evocation of the early days of cinema, which took a fistful of technical awards.

But one could argue they were honored not because of a sudden wave of nostalgia, but because the craft involved in making them was fresh and creative. “If they weren’t enormously inventive,’’ says film historian Leonard Maltin, “nothing else would have mattered.’’ Nobody, he reasons, had been crying out for a resurrection of the silent film or a movie that honors film pioneer Georges Melies.

But it was no coincidence that the Oscars brought back Crystal, who swooped in to save the day after Eddie Murphy pulled out. (Murphy had stepped down in solidarity with Brett Ratner, who resigned as producer of the show after making a gay slur.)

The choice of host also inevitably seemed like a reaction to the “young and hip’’ fiasco of last year’s show, which tried to lure younger viewers with its attractive young hosts, only to falter, especially because Franco was so relentlessly laid-back, it seemed like he wanted to be backstage partying. Meanwhile, when Crystal came on for a cameo, he received a standing ovation from the joke-starved crowd before he even spoke.

Some of Crystal’s routines Sunday won praise: The montage where he inserts himself into films was typically clever, and included a kiss on the lips from George Clooney ― never a bad thing.

The host’s best jokes were those that poked fun at the Oscars themselves: “Nothing takes the sting out of these tough economic times like watching a bunch of millionaires giving golden statues to each other,’’ he quipped.

But a few others fell flat, including what some felt was an ill-advised moment in blackface for Crystal when he reprised his old “Saturday Night Live’’ impersonation of Sammy Davis Jr.

Maltin, a veteran watcher of Oscar telecasts, pronounced Crystal a success.

“It wasn’t just his opening montage or song parody ― we’ve seen that before,’’ he said. “It was the way he kept the ceremony lively and punctuated it with zingers and laugh lines. Not too many people can do that.’’

Comedian Andy Borowitz, who always keeps up a vigorous Oscar-night Twitter feed, had a different perspective.

“At 82, Christopher Plummer is 18 years younger than this Oscar show’s jokes,’’ he tweeted.

At another point, he wrote “This shtick feels old,’’ then attributed the quote to his grandparents. At another point: “I never thought I’d say this, but I miss ... James Franco.’’

Age was a constant theme. When Plummer won his supporting actor Oscar ― the first of his career ― he spoke to the statuette: “You’re only two years older than me, darling.’’ Crystal then quipped that Plummer’s win had bumped the average age of winners up to 67.

And the night was young. Still to come: the 76-year-old Woody Allen’s first Oscar since 1987, the original screenplay award for “Midnight in Paris.’’ No, he wasn’t there to accept it ― he eschews award ceremonies ― and there was something comfortably familiar about that, too.

Meryl Streep’s award for “The Iron Lady,’’ her third Oscar, was also a tribute to longevity ― she’d been nominated 17 times and hadn’t won in 29 years. But she chose to speak of longevity of another kind: marital. “Everything I value most in our lives, you gave me,’’ Streep told husband Don, tearfully. She went on to give an equally emotional tribute to her makeup artist, J. Roy Helland, who had worked with her for 37 years.

Streep’s minor upset aside ― many had predicted Viola Davis to win for “The Help’’ ― it was a predictable night. But a few moments stood out for entertainment value: An exaggerated flash of leg by Angelina Jolie, for example, in a high-slit dress got so much attention it had its own Twitter feed, Angie’s Right Leg, which had more than 18,000 followers by Monday afternoon.

From Jolie’s leg to Jennifer Lopez’s, er, cleavage: Her stylist had to issue a statement officially denying speculation that too much of her breast had been revealed by the plunging V-neck of her Zuhair Murad gown.

And for all the talk of predictability, the unpredictability was in the details. If Octavia Spencer’s supporting actress Oscar for “The Help’’ was expected, the spontaneous standing ovation she inspired was not, and it was a highlight of the night. “I’m sorry, I’m freaking out!’’ she gushed. “Thank you world!’’

As for “The Artist’s’’ Jean Dujardin, the first Frenchman to win an acting Oscar, his speech was a winning mix of Gallic charm, mangled English, and sheer ebullience. (AP)