I really liked Justice League, and the quality of the film is such that I believe you could almost call it a "resounding success", especially if you judge it against the DC universe's previous output.
Since everyone already knows the plot, I will not bore you with a summary, but get straight to the review.
There are no weak spots in the acting. The entire main cast is doing a great job, including the main supporting characters. All the core characters are very well developed and written and are generally a joy to watch. It is here where I believe we can see Joss Whedon's writing most clearly. Of course, we might never know which elements in this film are his and which are not, but the characters (especially their interaction with each other) are strongly reminiscent of The Avengers. There are also a number of funny moments and amusing lines that feel strongly Whedonesque. The Flash is clearly the on-duty comic-relief character, but all characters have their moments of humour. If there is one thing which might be lacking – if we are going to keep the comparisons coming – it is a character with the charisma of Tony Stark or the charm of Captain America. But the Justice League characters are all new (in cinematic terms) and still have time to grow.
By the way, if we are throwing comparisons around anyway: it is not just the writing of the characters and the dialogue that bears similarities to The Avengers. In addition, Justice League also comes complete with a Marvel-style mid&post-credit-scene combo.
In super-hero-film terms, the story and the way it unfolds are not exactly revolutionary. But this is nevertheless a very well-written, well-paced film that is highly enjoyable. But of course this film also has its flaws. The film is stuffed full with a lot of things; but not too many things, I feel (although there are two supporting characters that, in my opinion, should have been cut from the film). Introducing three major Justice League members we have never seen before was always going to be difficult. After-pains, if you will, of Warner Brothers' decision to fast-track their DC universe. It went as well as possible under the circumstances. We get a “retrospective” origin story (through dialogue) for Cyborg, while The Flash and Aquaman have their origin only vaguely hinted at. Instead, The Flash gets a very nice introduction that shows us what makes him tick. It is Aquaman who gets a bit short-changed in the character-introduction department, in my opinion. Still, the way these character introductions are managed – being kept brief and to the point, and in the case of Aquaman being spread throughout the film – helps to avoid them weighing down the film or destroying the pace. And, as I said, the introductions of Cyborg and The Flash are really well done.
Batman is the one starting off the film by giving us an exposition courtesy of a long-distance-conversation with Alfred; an exposition that was not as enlightening as I would have wished for. Meanwhile, the re-introduction of Wonder Woman was slightly disappointing. A demi-goddess taking on a few UKIP-terrorists just hasn't the necessary pizzazz for me, I guess.
If Aquaman gets a bit short-changed in terms of origin story and background, the same could be said for the villain. The lore surrounding him is delivered in part by Wonder Woman re-telling a legend from the past, and in part by the villain himself (mostly through monologues). But somehow I did not fully grasp why he was doing what he was doing – possibly because the character occasionally mumbled so much it was not always possible to fully understand what he was saying. He was not the only one mumbling, by the way.
For people keen on finding parallels between this film and the MCU, pointing towards Marvel's sometimes slightly weak villains might check another box. Personally, I was more intrigued by some similarities this story has with the Lord of the Rings trilogy.
The film’s soundtrack is very good, and the film also looks great; but it has few of those epic sweeping shots that regularly turn into disappointment when you try to relive them on DVD – so for me, that is a plus. In addition, there are many enjoyable fight-sequences, even though one or two of them were a bit too long for my taste.
Again, this is a very good film. More enjoyable, for me personally, than Wonder Woman, and as such at least an 8 out of 10.