'Thor: The Dark World' review: Only stokes demand for a Loki spin-off

This latest Marvel flick is a fine, mildly fun adventure that's at its best whenever Loki is onscreen

In short: The Dark Elves - led by Malekith (Christopher Eccleston) - return to destroy the Nine Realms of Asgard, which includes Earth. (watch the trailer)

'Thor: The Dark World' is anchored by an Avenger with godlike powers (Chris Hemsworth) and a villain bent on eradicating Asgard. But the most interesting character, and the only one with a clear character arc, is Loki (Tom Hiddleston). Even imprisoned and shackled, Loki remains a wildcard who steals every scene he is in.

Unfortunately, Loki's inclusion in this sequel - from a narrative stance - is questionable at best. He's a tertiary character who feels shoehorned into the main plot - but he's easily the most entertaining part of 'The Dark World.' This is the not good news for a film with several other main characters.

Thor is a somewhat flat character, who clearly enjoys battle but is otherwise just a warrior crown prince pining for Jane Foster (Natalie Portman). Even less interesting is the Dark Elf Malekith, who is just a powerful baddie intent on destroying the Nine Realms. He has almost no back story nor the charisma to justify his lack of motivation. Malekith is less a motivated character than a plot device. Were it not for the unmitigated bungling of The Mandarin in 'Iron Man 3,' Malekith would easily win the title of 'Lamest Marvel Movie Villain.'

The 'aether' - a powerful weapon that Malekith desperately pursues - represents a discouraging trend in recent Marvel films.

'Iron Man 3' had Extremis, the 'Avengers' had the Tesseract and this 'Thor' sequel has its own MacGuffin - the 'aether.' The problem with these three latest Marvel movie 'weapons' is they're vague to a frustrating degree. Basically the only concrete information given about these weapons is: each one is incredibly dangerous (how or why exactly is often ill-explained) and the antagonist wants to use them for ... something.

The capabilities of each weapon are fuzzy at best. In the case of the 'aether,' it's unclear why a weapon capable of galactic catastrophe requires a host body - especially when it was quite safe for eons without a host body. And when the aether is attached to a host, it's unclear what new powers the host acquires.

Such ambiguity is a problem. At the very best, these ill-defined MacGuffins leave the impression the writers were just making it up as they went along. At the very worst, it's unforgivably lazy writing that takes away from any of the story's stakes.

Everything else about 'The Dark World' is either too convenient or a dangling plot thread.

A key location in the 'every-5,000-year-alignment-of-realms' of conveniently located one of busiest cities in the world. Thor's ancestors supposedly hid the aether away in a super secret location - but in a universe populated with billions of aliens, of course the one person who finds the aether is not searching for it and has no business stumbling across it. A whole, intriguing love triangle between Thor, Foster and the Asgardian warrior Sif (Jaimie Alexander) is teased, but absolutely ignored and unfulfilled after the first act. And for some reason, Dr. Erik Selvig (Stellan Skarsgård) shows up randomly, if only to serve as walking exposition and some 'crazy naked guy' visual gags.

'Thor: The Dark World' is simply too cluttered for its own good. Too many characters are unnecessarily included and only given fleeting moments to shine. A more streamlined cut of 'Thor 2' would give great weight to Thor as a character and Malekith as a credible adversary.

Final verdict: An underwhelming hero, a bland villain and some tedious, coincidence-based storytelling weigh down this 'Thor' sequel. Only the occasional big laugh and a scene-stealing Loki save 'The Dark World' from slipping below mediocrity.

Score: 3/5