The Marvel movie machine rumbles on with this enjoyable sequel. It will definitely help if you have previously seen the first Thor film and also "The Avengers" as this new film follows a specific continuity firmly planted in the Marvel universe. But of course movies like this have a built in audience and there is enough exposition by the characters to bring everyone else up to speed.
The original cast returns and pick up where they have left off. Chris Hemsworth embodies the Marvel version of Thor very well. Natalie Portman is his mortal girlfriend, Jane Foster. Anthony Hopkins hams it up as Odin and thankfully Tom Hiddleston returns as Loki raising the quality of the film every time he's on screen. Idris Elba also returns as Heimdall and is given more to do this time than just play Asgardian doorman. The villain this time is played by Christopher Ecclston barely recognizable under tons of makeup.
The story concerns Malekith, lord of the Dark Elves trying to destroy the nine realms with a dark force called the ether but the rambling plot is just an excuse for Thor to swing his mighty hammer and save the day. For the purist, the characters are drawn from the Marvel comics (with some minor tweaks and exceptions) and there is a deliberate bridge to the next Marvel film waiting for us during the credits. There is also a clever cameo, played for laughs like much of the movie itself.
The film doesn't have the gravitas of The Batman Franchise. It is, however, a fun romp that passes the time well until the next Marvel superhero saves the day.