I found the original film of this series surprisingly enjoyable (I am not a particular fan of the superhero genre, but somehow seem to watch a lot of the films) and posted my review of that film on this blog in December 2011. So I looked forward to this sequel with more than usual interest.
Thor: The Dark World is set a couple of years after the events in Thor, and has the hero still pining for the girl he left behind on Earth. In the meantime he has been sorting out the mess left by the events in the first film, and has just managed to finish that job when a new threat emerges – the Dark Elves, thought to have all died in a war with Odin's father long ago. But a rare convergence of the Nine Realms results in the reactivation of a deadly substance called Aether, and with it the surviving Elves who had used the Aether as a weapon. What's worse, the Aether has taken up residence inside Jane, Thor's human sweetheart (Natalie Portman), and is slowly killing her as well as making her the prime target of the Elves. Thor and his friends have their work cut out in battling the Elves, whose weaponry is far superior, while trying to prevent them from extracting the Aether from Jane.
As with the original film, many of the scenes are set on Earth (and even better, in London) and these are much more fun than the overblown fantasy film set of Asgard. The conjunction of the classical buildings of the old Royal Naval College in Greenwich with a vast alien spaceship is the most memorable scene in the film, making it worth seeing for that alone. Chris Hemsworth continues to do a good job as Thor, although not as impressively as in the original (not his fault; the script provides fewer opportunities to show his acting range) and what made the film particularly enjoyable was the retention of the humour which ran through the original. Often this can be found in very minor details that nonetheless caused me to laugh out loud, such as Thor, on entering a human house, politely hanging his Hammer on the coat stand.
So overall, a worthy successor to Thor, with an ending that sets up the next episode. By the way, the film doesn't end when the credits start to roll: there are both mid-credit and post-credit scenes, so don't switch off too soon!