It's an alt-universe Cold War story set in East Germany. Our heroes have to ride in giant robots, fight aliens (called BETA) and avoid getting dragged away for torture and execution by the Stasi. That last one's the trickiest. This is a cold, grey society where trust is for losers and anyone might inform on anyone else. One of our heroes shot her brother in the head for the Stasi, for instance.
I liked it quite a lot. I don't see many shows in that kind of setting. The aliens and giant robots keep us in a fantasy realm, obviously, but the show's still pretty serious about its brutal totalitarian regime. It develops the characters, some of whom start out in a pretty bad psychological place and are aggressively cold to other people. The law is whatever the Stasi wants it to be. Anyone can disappear. Trust no one. Believe no one. We see what it means to fight for a country you hate and don't believe in. How would you react if your Western allies snubbed and despised you as dogs of a police state? Theoretically all countries are fighting alongside each other, but there's a huge gap between them in technology, resources and attitudes.
The show's interested in its characters' psychology and motivations. In between the fighting and killing, the last episode is going to considerable trouble to explore why the most important players believe and act as they do, including the supporters of communist dictatorship. (If your world were under genocidal alien attack, would you also conclude that freedom and equality were dangerous?)
That said, though, this is an alt-universe. The plot might go anywhere. Our heroes might all get executed, but they might end up leading a revolution. Being an SF fantasy lets this show push its story further than a real-world story could have done. That's probably one of the show's strongest features.
Is there anything I don't like here? Well, there's fanservice. A show like this really didn't need to be yet another light novel adaptation with one male hero in an otherwise all-female cast, where the combat uniforms are skintight purple body suits that show off your big boobs. That said, though, the 666th TSF Squadron's gender balance is barely noticeable in practice. This show could hardly be further removed from an average harem anime. Eberbach in the early episodes absolutely isn't an audience identification fantasy, for a start.
The show's origins are surprising, though. There's a visual novel franchise (originally released as an adult game) called Muv-Luv, which had an alternate universe version called Muv-Luv Unlimited. This anime is adapted from a series of light novel prequels to the latter. Apparently one's reaction to this series will change if you're familiar with the Muv-Luv universe, but unfortunately that's almost impossible for English-speakers. This is the franchise's first anime adaptation in any form, while the games have never been translated or licensed for international release. I'll just have to accept that I've missed out on lots of background and allusions... but to be honest I'm comfortable with that and I thought this anime stood alone just fine.
It's a meaty show, I think. It's distinctive, hard-hitting and offers you plenty to dig into. Anyone can die and anyone can be dragged away to be tortured. Don't expect bloodless heroic victories. At the same time, though, there's enough fantasy in the premise that it's entertaining to watch. It's not gruelling. The show won't make you want to slit your wrists. In an anime industry that repeats itself all the time, I hadn't seen anything quite like this show before.