I checked the film out in 3-D. I was initially trying to specifically see the 2-D showing given Marvel's 3-D conversions aren't really all that great. Unfortunately my initial worry was proven true as Thor's 3-D conversion isn't very good with many ghosting issues. Scenes continue to be shot with disregard for the sensibilities of 3-D prior to conversion, and overall you're much better off avoiding the 3-D version if you can help it.
The current theme that seems to be going on is that our heroes have all been affected or changed in some way by the events of the Avengers. In Iron man 3, Tony Stark was dealing with his traumas from a near death experience. In Thor: The Dark World, Thor is dealing with the pressures of having his brother Loki locked behind bars for his trecherous actions and the effect it is having on his family. He himself has become more sullen, unable to celebrate and be as mirthful as he used to be, while increasingly becoming reluctant to take the throne and become king of Asgard. Not to mention, he misses Jane, the woman he fell in love with on Earth in the first film. However, due to all the copmlications following Loki's rebellion, he has been busy fighting to bring peace back to the realms that Asgard controls and keeping things in order.
Back on Earth, Jane and co. stumble upon some strange phenomena happening around London. While investigating it, Jane finds herself transported to a strange place where a strange fluid energy infects her body. As it turns out, this fluid-like substance in a powerful force that was locked away by Thor's grandfather who took it from a race of beings called the Dark Elves who would use it to destroy the universe. Various things from Jane's arrival and infection, as well as the return of the Dark Elves are set in motion due to the universal alingment of the realms; an occurence that only happens every couple thousands of years. When Heimdall, whom Thor had asked to keep a watch over Jane, loses sight of her... Thor rushes to try and find her. However, he is not the only one after her, as the Dark Elves are also set on finding her and using what she carries to once again achieve their initial goal of destroying the known universe; and they're willing to bring total war to Asgard if they have to.
'Thor: The Dark World' not only brings back the fantasy and levity that its first film debut achieved, but also elevates the Marvel Film Universe as a whole, setting in motion things that will really leave fans salivating for more. It's a suitable follow up in scope after the Avengers that brings the action and high stakes that put the cosmos at dire risk. It also ratchets up the drama between Thor and Loki whom Thor turns to out of desperation, all the while knowing that Loki will find some way to betray him. It is the two of them that really make the film, and there will be resolutions and revelations that will shock viewers when they happen.
If you're a fan of the various Marvel films, and the Avengers universe, then 'Thor: The Dark World' is a must-see that is taking us to bolder territory. When the credits begin to roll, stick around for an additional scene that will really excite fans, and also stay until the very end of the credits for yet another additional scene that'll make you smile! Great things are in store, and comic fans who know their stuff will know why!