All credit to the makers of Thor 2 - The Dark World, they aren't underestimating their audience. See this film, and you'll have to hand-wave not just the magical space vikings, but the whole of Stan Lee's gimcrack pseudo-Norse cosmology.
And a pack of dark elves from the dawn of time cosplaying the Borg.
And the notion that Greenwich Palace is three stops from anywhere on the Tube.
Thor 2 gets away with all of this with a positively rabid self-belief and a willingness to wear its canon lightly - i.e. stuff is, now let's tell a story! It follows Iron Man 3 and Avengers Assemble in being the third solid Marvel film in a row, after the erratic qualities of earlier efforts, including its predecessor.
It builds on the merits of the original - chiefly gorgeous art direction, a great start and fanning the cult of Hiddlestone - by better integrating the small-scale character-driven moments and the epic. Plus Natalie Portman gets to save the world(s) in a major advance on her love interest role first time around.
Midgard and Asgard in perfect harmony, or as near as darn it.