No Game No Life was one of the worst animes I ever watched, everything in this anime was like mediocre to bad, but at least was fun to watch, all the references to others shows make me laughing at least. For No Game No Life Zero I can't say that tho.
In brief, the movie is boring as fuck, felt like would never end. All this "dark atmosphere" that the movie is trying to construct fails A LOT. But, let's talk about every aspect separately:

First of all, the two main characters, Riku and Schwi. They have a design that is LITERALLY a copy and paste from Sora and Shiro. I know, I know, the movie is trying to make like a parallel, but man, is so fucking identical.

Riku even have that damn Sora's sadist smile which I fucking hate, and Schwi is just another source of incest and pedophile jokes like Shiro (literally, the first scene with Schwi already have a sex/incest joke). For their personality, they are both annoying, this drama of being in war and people dying making Riku mad and shit is laughable.
The relationship between them is horrible. All of this shit of Schwi wanting to know about human emotions leads the movie to a artificial romance that just Kouhei from Grand Blue would like.

For the plot, all I can say is that the plot is boring. I don't really care about the eternal war that devasted the NGNL world. With like 30 minutes of movie elapsed I couldn't take it anymore. NGNL0 tries to build a more dark and complex plot than the main series, but it fails hard. Well, the plot of the anime is not to good too, but at least it was fun to watch, the comedy part with all the references to others shows and that gorgeous pink color palette is good enough to make it worth to watch; the movie, on the other hand, don't have all that beautiful visuals or the comedy part.

Aside from that let's talk about the good things.
I have to admit, the production is fucking awesome and the director has made a good job too. This scene (along side of the other action scenes) was really wonderful, visually speaking.

The movie almost don't have pedophile fan service too, this is a evolution!

At the end, this movie is shit, if was not the amazing animation this would be on the bottom of my list. I can't take all of this loli fan service and jokes with sex or incest as the comic relief. I fucking hate NGNL, I'm glad that the light novels are banned from Amazon

NOTE: If you scrolled down just to see the score keep going, I do this too so whathever.