There have been a few minor changes to the second leg of Britney Spears' "Circus" tour, but the over-the-top concept and the dazzling presence of the pop star and sex icon in concert are constants that remain.

Reviews have been tumbling in as Spears kicked off her return to North America last Thursday, and with last night as the christening of her three-night run at New York's Madison Square Garden. Check out some quotes below.

Featured were a couple change-ups. For one, the dance number surrounding opening song "Circus" leaves Spears a little less molested by clowns and surrounded by more acrobats in bondage gear. Also, the "Circus" album track "Mannequin" has made its way into the rotation.

What remains, of course is the twisted introduction to the three-ring spectacle by self-professed queen of gossip Perez Hilton, dressed as what appears to be the Queen of Hearts (a generous irony) Check out the video below).

But that's a title Spears has been, perhaps inadvertently, trying to gain with this ultra R-rated tour: that she's no longer a pop princess, but royalty of a higher rank.

Spears' Circus tour stays on the road through the end of this month.

MTV: Let me echo the sentiments of her fans, folks. Yep, she's baaaaaaack! And I had the time of my life at her concert... So what about that whole lip-synching thing? I get it now. The fact that Britney probably doesn't sing live is a moot point. Of the dozens of fans I chatted with before and after the show, they were there to see a spectacle, and Britney and the Circus tour definitely delivered just that. I finally understand that having a giant sing-along in a dark room with Britney Spears could be just as transcendent a concertgoing experience as seeing Grizzly Bear sing complex harmonies live with a children's choir.

Ottawa Citizen: The moves were fairly vulgar, and Spears executed them with the detached air of a robot instead of the feisty defiance that would have matched the lyrics... Just two dates into a North American tour that stops at Madison Square Gardens this weekend, Spears needs to be at the top of her game; after all, she's a prodigal daughter on the verge of a grand homecoming. Judging by Friday night's concert, she's almost ready to slay the masses.

The Improper: Brit made a grand entrance descending from the ceiling wearing a shiny metal bodysuit. She launched right into her single "Circus," then hopped in a cage with male dancers dressed in S&M gear for "Piece of Me." Along the way she pole danced and played the dominatrix, male dancers to do push-ups for her, and gave shout-outs to the crowd. "What's up New York?" she yelled before diving into "I'm a Slave 4 U" in sparkly black bodysuit.

The New York Post: She doesn't sing, and dances like a little bear? Not our Britney. Well, maybe that's the point of all the distractions in Spears' Circus Tour. The hope is that in the hubbub of the concert's razzle-dazzle, which includes juggling, kung-fu swordplay, creepy clowns and acrobats -- not to mention girls in unmentionables -- you might not notice that Spears is almost all vamp and no vocals. Spears makes an exception to the no-singing rule by actually using her pipes to belt out the sappy slow ballad "Everytime"...She and the production were entertaining.