AJ Black’s review published on Letterboxd :
It's interesting going back and rewatching Thor once you've seen The Avengers, because it now seems oddly small scale! And while, of course, that's not at all the case, Kenneth Branagh's stab at putting his stamp on the Marvel-verse doesn't exactly thrill in the way it did first time around - but its fair to say he delivers a strong introductory story to one of Marvel's more 'out there' characters and origin tales, managing to balance big-budget action with the sweeping, cod-Shakespearean scope you'd expect from such an exponent of the Bard.
It's riven in myth and legend, the entire production bearing that out, but Branagh and his screenwriters wisely do their best to ground Thor in self-effacing humour and humanity, preventing the thing going off the rails into the OTT pomposity it could so easily have succumbed to. Though in hindsight he perhaps is better written by Joss Whedon, Thor is well brought to life by Chris Hemsworth - showing well his journey from arrogant king-in-waiting to humble hero; but while Anthony Hopkins, Stellan Skarsgard, Idris Elba & Natalie Portman all provide very solid support in nicely played supporting roles, much as he threatens to in The Avengers, Tom Hiddleston steals the show as Loki - quite brilliantly bringing to life a lost, jealous soul corrupted by power, bouncing perfectly off Hemsworth, even if perhaps he doesn't get quite enough screen time. Speaking of, Branagh wisely doesn't inflate the piece beyond its means, detailing a rather epic story in a concise running time with good, unique beats of incident around the character drama and comedy, reigining in the Shakespearian nods before they get unwieldy. It's a shame he won't be returning to helm the sequel.
That said, it's not quite my favourite Marvel movie - though it's sumptously brought to life, the plot occasionally wanders and the Thor/Jane Porter dynamic isn't perhaps explored in enough depth, but it remains probably the most solid, cohesive build-up movie to The Avengers outside of the first Iron Man. Don't forget the post-credits teaser too - definitely one of the best building up to the main event.