(Keep in mind, this review has been written after the 4th episode came out - it may not be representative of the entire series, though from how things are progressing so far, I don't see how that could change the validity of this review in any drastic way.)
When I first came across this anime, I thought to myself "what a time to be alive!" Cute girls that are personifications of guns? Sign me up! I'm a shameless gun enthusiast, so this was supposed to be a dream-come-true. Little did I know it was going to be the most disappointing series of this season.
The story isn't bad or good, it's just kind of there. The one thing I'd say is that it's hard to follow at first because we are immediately thrust into what seems to be a major confrontation with no knowledge of what is actually going on and why, besides some cryptic voiceover explaining something about something. After 4 episodes I'm still not sure what's going on apart from that Sangvis are the bad guys with guns, and Griffin are the good guys with guns, and there was some AI rebellion or something. Sounds generic.
Art is ok-ish if you don't mind stills of cute girls. Most action scenes take no more than 3 stills spliced together, and larger set pieces rely on animation loops with an occasional, unimpressive explosion or a bunch of muzzle flashes and bullet trails. The characters themselves lack any expression, but I guess they're mechanical dolls so that kind of explains it.
Now, to get to the nitty-gritty: the gun models. For the most part they're well done for static models, though in some instances they lack detail or, as is the case with MG3, they are obscured most of the time so we never really get a good look at those beauties. Which is a shame, because that's the biggest selling point of this anime, and so far it's been a let-down. Especially since there are no moving parts on those guns, so the most dynamic you'll get is the muzzle flash. I don't think we even saw a single reloading animation so far. Or any kind of mechanical operation of the guns for that matter. They are just there, static models that you can't even get a good look of because they're mostly obscured or there for like 2 seconds before the scene cuts.
Moving on to the sounds, they are dreadful. The music is some horrible, generic synth-whatever that you'd only hear in a browser game. Dialogues and VA are fine, not much to say about that.
But the gun sounds... they're horrible. They're exclusively generic, stock sounds pulled from some royalty-free library that you heard a million times before while playing low-budget games. Whenever I hear a gunshot in this anime I literally have a flashback to the time I played a game that sound was used in before. It's a horrible, jarring experience and any gun enthusiast will be immediately put off by that. If they really wanted to sell those gunfights, they'd have sent a crew over to a gun range in the US and recorded the sounds those guns make in real life. It's not that difficult or expensive, but I guess they wanted to save money so they went with royalty-free sounds. Disappointing, to say the least.
Characters are there. Not much more to say. Just your typical array of tropes and stereotypes. But the biggest disappointment was the anime's focus on the AR15 pattern rifles as the main protagonists of the series. I mean, you have an anime about personifications of guns, and instead of showing of how diverse firearms can be, you choose a bunch of AR15 pattern rifles, which look almost the same, function almost the same, and are essentially different configurations of the same damn firearm. Sure, in the later episodes we get a few glimpses of other firearms, like the German MG3, G36 and MP5, we get a brief introduction to MAC-10 and a couple of Russian firearms like PPSh-41 and Mosin-Nagant, but for the most part they play minor roles and we only get a couple of short glimpses at them before the story picks back up with the AR15 family. So if you like AR15 pattern rifles, you may be somewhat satisfied, but not really.
Overall, it's a huge disappointment. Not only does this series fail to live up to it's premise, it somehow almost intentionally avoids it for the most part. In my opinion it's nothing but a cash-grab from whoever sponsored this nonsense. If you're a gun enthusiast like myself, you're not losing anything by skipping this one.