People always get very excited for these movies but lets be honest; when was the last truly great DC or Marvel animated movie made? These movies never really live up to expectations but then again, it's of course also extremely hard to please the superhero crowd. Everybody has their own personal favorite and 'right' interpretation for the character in his or her mind, so whenever a movie is changing things around or doesn't feature and portrays their favorite superhero in a prominent and good enough way, people are going to complain and end up feeling disappointed by this movie.
Same thing no doubt is going to happen with this movie as well, especially seeing how it doesn't feature 1 or 2 well known superheroes in it but a whole bunch of them. After all, this is a 'Justice League' movie, even though at no point do any of the characters in this movie refer to the 'Justice League' and the superheroes don't even team up as such yet in this movie. It's basically an origin movie for the 'Justice League', in which some of the characters meet- and team up with each other for the very first time.
So really, everybody is going to most likely have a very different opinion of this movie. Personally, I quite liked the movie, though it definitely wasn't ever being a great or very surprising one, in any way.
It's kind of annoying how this is yet another 'origins' story, in which all of the characters meet each other for the very first time, even while there are of course plenty of comics and movies out there in which, Superman and Batman for instance, have met and teamed up in already. But OK, I was able to look past all of this and watched this movie with an open and empty mind, pretending that it truly was the first time that all of the characters met. And as an origins story, it really isn't anything too bad.
It still relies on it that you know all about everybody's background and personality already though. So it definitely helps if you're familiar with all of the characters and their universe already. Not that the movie is very hard or impossible to follow if you don't already know all about Wonder Woman's background or the Green Lantern's origins but like I said, it helps if you do.
The movie does a fairly good job balancing things out, when it comes down to the amount of screen time for all of its characters. It also does a good job with showing off each of their powers and specialties, without ever making one character seem more powerful or capable than the other. It handles most of the characters well in my opinion.
The story itself...well, it's all some very basic stuff really. An evil alien comes down to Earth and guess what, he wants to destroy it. Really nothing too original and the movie itself also features hardly anything original in it. It's all a bit too simplistic for my taste but at least it still was fun and good to see how all of the superhero characters teamed up and used to powers to prevent things from happening.
There also still were some few minor touches to the story that I still liked though. I liked how the 'normal' humans were starting to turn against the superheroes and questioned their motives and feared their powers and what they potentially would be capable off. But the movie is doing far too little with all of this really. There aren't really any good human characters in this movie anyway and the story was mostly just all about its superheroes instead. There truly were plenty of opportunities for the movie to turn into something 'deeper' and more interesting at times but it prefers to stay simplistic and straightforward instead, in favor of its entertainment.
The animations are also pretty basic and straightforward but it's the type of animation that have always suited some of the superheroes well. Granted that it's the type of animation that suits the Batman character better than the Superman character in my opinion but that's all just a matter of taste really. I wasn't too fond though of the fact that the movie also felt the need to CG certain things, which wasn't quite in tone with the rest of the movie and worked out far too distracting. It besides all seemed pretty pointless to me, unless they ran out of time or money and they simply had no other choice.
The voice acting was pretty good all throughout but I only wasn't that fond of Jason O'Mara as Bruce Wayne/Batman. He wasn't quite deep or charismatic enough but oh well, at least everybody else sounded pretty good to me, so I'm not making a too big issue out of it.
The attempts at comedy weren't always too great or successful but at the same time it still helped to keep things light and pleasant to watch. Despite all my criticism, I still enjoyed this movie and I'm sure that most of the fans of the characters are going to enjoy this movie as well.
Definitely one of the better and more enjoyable, recent, animated superhero movies, in my opinion.