Justice League: Gods and Monsters is a much welcomed return to the quality standard DC Animated established that was a bit lacking in the last few entries since Justice League War, Son of Batman and others. What makes it even more special is that it isn't based on any material but is a new, original take on the Justice League.
If you haven't seen the free-to-watch shorts, know that the almost all characters have little to none in common with their original, classic counterparts and only share the same handles and loosely the same function within the league. Superman is now the son of Zodd, Batman has no problems killing villains by sucking their blood Dracula-style and Wonder Woman has a completely different background. New faces, new abilities, new origins and relations etc. Considering how much was already done in Batman TAS, Superman TAS, Batman Beyond and Justice League, it's really refreshing to see Bruce Timm back doing new things while still maintaining the similar feel and quality the classic Justice League series are known for. While it's not quite on par with the best episodes of the Diniverse/Timmverse, it's definitely up there with the good ones.
A good portion of the fun is discovering familiar characters and see what has changed about them. You'll see familiar faces or just familiar outfits, notice what changed on the first sight and wonder what what else is new about that character and where they'll go with him. The good thing about it that they don't feel neither better nor worse, gimmicky or unnecessary, just different and effective in waking my curiosity and it makes the impression the makers had fun with it for the most part. It succeeds where Justice League War, another alternate universe JLA movie, failed.
The story tells the origin of each of the three Justice League members with a plot-line in the current time and is pretty much straight forward, but interesting enough and well paced. The downside of is that you have to be familiar with the DC universe to a degree, otherwise you'll be wondering about the function of a couple of characters with small screen time and won't care for their destinies as much.
The action is a bit lacking, but the focus is more on storytelling and characters anyways, so its a good trade off. A change here is now that the JL member are much more ruthless and have less remorse, which results in some bloody kills. It's a good thing that the writers have more freedom in that regard, however in this case it feels a bit forced and clumsy. It feels weird seeing them crush some goons with a huge and heavy door and seeing blood coming out underneath it. Perhaps I'm just too used to the DC Animated series, but it felt more out of place rather than adding anything to it. They got it right in a few scenes, but for the most part it felt just like a gimmick - violence just to show they can do it, without any meaningful impact or purpose.
Overall it is good, solid and refreshing fun. It's a good mix of old and new with very similar art-style to the series and is a great way to start things off. It has it's faults like a few characters being degraded to throwaways (Darkseid, Harley Quinn in the shorts...) or not being more subtle on certain things, but the rest makes easily up for it. There is much potential and hopefully we'll see more of it, maybe even in a form of a series just like in the old days. It's deserves a shot.