Thor: The Dark World reviews are in and the critics say the second installment of Thor saga is not perfect but is fun and worthwhile.

The new sequel featuring Chris Hemsworth and Natalie Portman, grossed an estimated $7.1 million in previews on Thursday night and Friday mid-night screenings and $158.2 million more overseas.

In 2011, Thor got $3.2 million during its midnight start; however, during the weekend experts forecast foretold new chapter could rise $90 million more getting into Iron Man margin with 98.6 million in its debut in 2008.

Some reviewers are complaining because they think filmmakers place more effort on greater CGI graphics and special effects instead of a well-developed story.

"Bigger is not always better. 'Thor: The Dark World' pumps up the action and special effects and loses some of the human element that made the original 'Thor' (2011) something charming and unexpected," Mick LaSalle wrote for San Francisco Chronicle.

LaSalle review is part of a very divided opinion among dozens of critics released recently.

Today, Thor: The Dark World is now playing in United States theaters after a well-performed premiere in London on Oct. 22.