Thor: Tales of Asgard isn’t a bad movie. But I wouldn’t call it a good one either. Its most prominent feature is having Loki still as a moderately good guy, though his later slide to the dark side is hinted at all the time. The art style is the strange beast that came up in the wake of the manga rising, a fusion of the most generic elements of manga with western style elements (the cover of the movie is an annoying deception, showing a completely different art style than what is inside). It’s not an art direction I like, but it gets the job done most of the time. Though, like with the style, everything about the movie screams: mediocre.
The plot is banal and the characters are bland and cliche. It’s a watchable movie, but I wish they did something more than just show the adventures of young Thor. One thing I found really annoying was one of the good characters doing a complete flip-flop toward evil, that while understandable, seemed to contradict his depiction up to this point. There were no subtle hints that he would turn evil (okay, I know, he’s dark elf and evil in Marvel proper, but still). It’s far from any epic or heroic saga you expect with someone like Thor as the main character.