Following [article id="1624952"]premieres on Tuesday in 17 cities[/article] around the globe, "Michael Jackson's This Is It" began screening for the public after midnight. The documentary about the King of Pop's prep work for his planned concert series has broken international ticket-sales records and online ticket outlets have reported thousand of sellouts. Insiders have predicted [article id="1623916"]the film could pull in $250 million[/article] in its first five days.

That's quite a bit of hype. Now people are actually getting to see the movie. What have they been saying? What sort of portrait of MJ does the film paint? As the film opens for its two-week theatrical run, MTV News has gathered the critics' reviews.

What the film does first and foremost is give fans an idea of what the London concerts would have been like. And as Andrew Barker writes in Variety, the doc makes clear that the shows "would have almost certainly signaled one of the most dramatic comebacks in pop music history. The rehearsal footage on display in 'Michael Jackson's This Is It' is evidence enough to draw that conclusion, providing a solid basis to imagine the final product while also giving a heretofore unseen glimpse of the star's creative process."

What makes reviewers like Barker draw such conclusions? The fact that at the age of 50, and certainly frail, MJ still maintained the talent of years past. "Even when just marking his movements, Jackson shows signs of the physical and vocal fluidity and sheer charisma that he retained," explains Elysa Gardner of USA Today. "Watching him work with his band and backup singers and dancers, one senses the excitement and joy that talented performers can bring to the often grueling process of assembling a show."

Not everyone was wowed by the straightforward presentation of rehearsal and behind-the-scenes footage. Drew McWeeny at HitFix.com craved a framework, a story that touched on the facts surrounding the concerts and Jackson's death in June. "The first thing you need to do is set up interviews to help place that footage in context, and you need to decide what narrative it is that you're going to craft to help make the film into an experience and not just a clips package," he argued. "Those choices were never made here, and the result is flabby, inert."

Though the doc does show off Jackson's working style and personality, some suggested that viewers never get a full picture of the man himself. Of course, that doesn't mean the film is anything less compelling because of it. "It's a bit much to claim it's any kind of viable substitute for the live show, and since Jackson avoids conversation as much as is humanly possible it's also a bit much to claim we get to know anything more about how he ticks," writes Andrew Pulver in the UK's Guardian newspaper. "But 'This Is It' is a testament of a kind, and one that is no disgrace to his memory."

In the end, as most reviewers pointed out, it's all about the music -- and in this respect, the documentary delivers. " 'This Is It' includes most of Jackson's hit songs like 'Billie Jean,' 'Thriller,' 'I'll Be There' and 'Beat It,' " writes Clay Cane on BET.com. "The viewer gets an intimate look at Jackson's rehearsal style, his quest for perfection and gifted attention to microscopic detail. ... It's truly fascinating to watch and makes you want to study so you can somehow factor these skills into your own life. It would be similar to viewing footage of Beethoven composing a musical number or Picasso painting a portrait. This glimpse into MJ's genius is awe-inspiring."

Check out everything we've got on "Michael Jackson's This Is It."