LOS ANGELES?Michael Jackson's "This Is It" blazed across worldwide cinema screens Tuesday, but the movie will do little to answer lingering questions swirling around the singer's final days.

Distilling more than 100 hours of previously unseen rehearsal footage into a two-hour documentary, the film will no doubt delight die-hard fans of Jackson seeking a fitting epitaph for the musical superstar.

Scenes showing Jackson interacting with cast from his London extravaganza depict a hard-working, funny and prodigiously talented entertainer.

The film unfolds as a succession of greatest hits, giving fans a glimpse of the lavish concert performances planned for London that Jackson hoped would signal his return to form.

Memorable sequences include a 3D video of "Thriller" and an effects-laden rendition of "Smooth Criminal" where he pops up alongside Hollywood legend Rita Hayworth in the 1946 film noir classic "Gilda."

In another sequence, concert extras are left applauding as Jackson produces a virtuoso display of dancing to the strains of "Billie Jean."

Earlier Tuesday, movie director and concert choreographer Kenny Ortega told reporters the film shows Jackson's ambitious plans for his comeback.

"You see Michael's vision for 'This Is It' ... You see him onstage as if he were standing in front of a full house," he told the Los Angeles Times.

"I hope the fans find satisfaction, that fans will understand what Michael had planned for them."

Early reviews of the movie were positive.

The USA Today newspaper said that while the film did not "restore Jackson to his past glory" it did "offer glimpses of his bygone greatness."

"The songs remind us that early this summer, the world lost a genuine, if genuinely troubled, star," the paper opined.

Other US reviews meanwhile applauded Ortega's decision to resist turning the film into a mawkish requiem for Jackson.

"You could watch the entire movie and not know that Michael Jackson is now dead," the Florida Times-Union reported. That's how restrained, how remarkably unsentimental, is this exuberant, astonishingly entertaining concert film.

"It doesn't try to deify him or explain him, and it's all the more moving for that understatement."