Thor has managed to surprise me yet again. I liked this movie a lot and I actually think its one of the better Marvel era sequels. It didn't just redo the original story. It expanded Thor's world and used all the characters to make you hooked into what was a VERY sci-fi movie. Loki was of course back and was once again the best part of the movie. He stole every scene he was in and the movie picked up tremendously when he was on screen. The story, tempo and side characters were all great. And even though the new villains were basically explained by the opening narration, I still thought that they were great too.
I would absolutely recommend any Marvel fans checking this out. It's a great continuation of the Thor and Marvel universe stories.