No Game No Life is a light novel series (10 volumes and counting). It got a twelve-episode TV series in 2014 that I really enjoyed, but more importantly it looks as if enough people agreed that it's now been given a movie too. It's based on the 6th light novel, but it's a prequel set six thousand years before everything else, starring characters who are merely remininiscent of the main series protagonists, Sora and Shiro. (Similar character designs and same voices, but very different origins, motivations and relationships. They're precursors. It's up to the audience to start speculating about reincarnation.)
The tone's very different. The 2014 series was an isekai power fantasy, with two super-gamer siblings travelling to a world where war has been abolished and instead people play games. Chess, draughts, poker, whatever. Win enough games and you can rule the world. (Apparently this is a lot like an earlier show, Problem Children Are Coming from Another World, Aren't They?, which I must watch one day.) This show is super-cool and it's great fun watching Sora and Shiro out-thinking all their opponents.
The 2017 film, on the other hand, is set in a war-torn hellhole. The first thing we see our hero (Riku) do is order one of his subordinates to sacrifice himself as a decoy. He's had to send lots of people to their deaths and it's turned him into a savage, seething despair monster. Offer him the secret of everything and he'll say "no". His goal's just to keep surviving one more day. "How many more will you make me kill?" There's no hope in his life, only pain. He's a million miles away from the indestructibility of Sora and Shiro, instead being a fragile, angry man who's constantly on the edge of death and might fail at any time.
As for Schwi, she's an Ex-Machina. This goes way beyond "robot". The Ex-Machina are a gestalt machine race who are all in mental communication with each other and who are in the process of exterminating humanity. One of Schwi's big questions is "why aren't you all dead?" She looks like a Terminator that's not even trying any more, with flesh only covering about two-thirds of her body. You can see the gears, wheels, blades, etc. underneath. She has two tails. She's got a big frisbee in her head. That said, though, she's been excommunicated from the Ex-Machina hive mind and she's researching the human heart. (Her knowledge at first is limited. She introduces herself by trying to be a sexbot and assuming that Riku's into sister incest fantasies, thus demonstrating that this really is anime after all.)
The setting's desperately grim. Humanity's on the brink and Riku's hostile and desperate. The film itself isn't quite that bad, thanks partly to a rich vein of dirty humour. (It's often very funny. I laughed aloud.) However our heroes' victories are all hard-earned and the drama's much more hard-hitting than in the parent series.
It has more weight. It's a huge deal when Riku finds his confidence and starts acting more like Sora.
The film's also a romance, in a way that the 2014 series couldn't be. (They're step-siblings, but still.) It's actually quite well done, albeit occasionally played for dodgy laughs.
This film will go down better with a much broader audience than the 2014 series did. It's strong stuff. Everything's life-or-death and there's no such thing as plot immunity. There's no guarantee whatsoever that our two main characters will survive and indeed we'd be pretty surprised if they did. Victory will have a cost and you can tell that tragedy could be waiting around any corner. The film's both triumphant and very dark. It can be really cool, but also emotional. It's very good, but also by the same token doesn't have the power fantasy thing that the 2014 series did so cleverly to make it a blast. (Power fantasies aren't necessarily bad, although it's unquestionably a genre where Sturgeon's Law goes nuclear. Superhero comics are also power fantasies, after all.) The only real downside, I think, is that the ending's kind of weird, abstract and messy... but then it comes full circle again with a framing story and you feel the emotion again.
You don't need to have watched the 2014 series to enjoy this film, although I'd recommend having done so. It'll help. If you're into apocalyptic SF/fantasy, this one's well worth a look.