What's this about and what does it do that's different and/or better than the bazillion other post-apoc games out there?
Mechanically, it doesn't do a lot of things differently from other games. There's a primal urges vs. logic mechanic in there that has to be taken into account when doing character builds (I'm pretty sure that there are a few games that do something to this effect and I'm pretty sure I own a couple of those), but that's pretty much it. Is it the best system ever? No, but it has a good crunch-simplicity balance. WoD had a worse system (simple as hell in principle, until you had to keep a bunch of photocopied pages to remember what you could do with disciplines X and Y, and the buckets of D10s, and fights that took forever, and shitty critical failure mechanics that weren't addressed until 2E, and...) and I don't see anyone calling V:TM or W:TA shit, I had great fun with those games back in the day, but here we are.
In regards to the setting: the apocalypse occurred 400 years prior to the setting's current day, due to an impact event. The impact itself could have been prevented, as the United Nations had planned to nuke the asteroids, but a hidden hand (a corporation led by a megalomaniac) thwarted the plan, the nukes missed, and the meteors hit the planet, causing tidal waves and shifting the rotation axis (so Europe is further north than it should). The megalomaniac wanted to cause a societal collapse to start civilization anew in accordance to his own ideas, and the way he did it was by building a network of bunkers and placing brainwashed volunteers in cryostasis in those, waking them up in 100 year intervals so that the 100-years group would lay the groundwork for the 200-years group, and so on (there are 6 generations in total IIRC). What the megalomaniac guy failed to foresee is that the meteors carried alien life (in the form of some spores that taint the ground, infect humans and wildlife, and turn them monsters in service of an alien intelligence with an unknown agenda) and that a group of hackers would mess the order in which the bunker dwellers would wake up.
There are several groups about, mostly the cults. They are classified as such (even though most are not about religion) because they are the result of weaponized memetics by the megalomaniac guy (basically, the descendants of the bunker dwellers that woke up in the wrong order), and I guess the name may come from cargo cults, in that they have customs that are independent from their ethnic origin (also, some of the cults with a religious bent have more presence in some parts of the world than in others). There are:
-The Spitalians: basically medics, they are the ones fighting the spore infestations and researching the alien lifeform and its effects.
-Anabaptists: think Christian fundies, sans God, they eschew modern technology and fight the alien monsters using fire, the sword, and distilled oils from the alien fungi.
-Palers: they worship the sleepers in stasis in the bunkers and their computer systems as if they were gods, are pale and can't see very well in bright light.
-Apocalyptics: basically, hedonists and undistilled alien fungus peddlers (it's used as a narcotic in the game, even though too much use will irrevocably infect the user), they are reviled by most cults.
-Clanners: mostly descendants of whoever survived outside of the bunkers, they have a hodgepodge of ancient customs, tech level can be anywhere between stone age and space age.
-Chroniclers: the descendants of the hackers that messed with the sleepers' waking order, they maintain what's left of the Internet, their inner circle keeps tabs on the megalomaniac's plans, they also print a cryptocurrency that is the de facto currency of most of Europe.
-Hellvetics: swiss mercennaries with space-age tech, they keep to the borders of what used to be Switzerland unless there's money to be made.
-Judges: think Judge Dredd with early 18th century tech. They use hammers and muzzle-loading guns to bring frontier justice to the far reaches of central Europe, and they are based in the city of Justitian (ruins of Berlin IIRC).
-Scrappers: these are your plain old scavengers, with a rudimentary guild structure. They mostly sell their hauls to Chroniclers.
-Jehameddans: a hodge podge of Christianity, Islam and Judaism. They have a mythical prophet called Jehammed, but their actual leader is a guy called Aries who is one of the original henchmen of the megalomaniac guy, made pretty much immortal through nanotechnology (there are a bunch more of his kind still roaming the Earth); he uses nanites to heal himself and manipulate people, and keeps a praetorian guard that he sends all over the place, and get this: he remotes into their brains via a sophisticated helmet those guys have to wear, and he does all the dirty work himself by remote control.
There are also some cults from Africa, even though the main setting is western and central Europe (in fact, in the game the fate of the world beyond Europe between Spain and Poland, and Africa to the south of Niger is pretty much unknown):
-Neolybians: wealthy merchants, they are the Chroniclers' main competition (although they have very different agendas)
-Scourgers: the descendants of africans who were in the middle of a UN-backed European military intervention when the shit hit the fan. They managed to overpower the foreign troops, who could not expect reinforcements anymore. They still carry UN gear and have massive Surge Tanks (mobile fortresses).
-Anubians: occultists with a bent for the old Egyptian pantheon. They have rituals that somehow work (there is a certain element of magical realism to the setting).
There is also a metaplot that goes on along the game's multiple sourcebooks, and it's a pretty decent one. It's about one of the immortals I referenced in the Jehammedans summary feeling betrayed by the megalomaniac guy (who is in an orbital station having a few pints and waiting for all this mess to blow over, while he left his closest henchmen out to dry on Earth) and chasing the components of an artifact that can give him the altitude, azimurth and so on of the space station, and the components for either a railgun or a directed energy weapon to shoot the aforementioned station. The players can stumble into all of this mess if the GM wants to.
The production values are THE BEST of any RPGs out there, and these guys are doing it as a labour of love: they haven't reached the break-even in this project and they don't care if they never do (as they admitted in an interview); they are doing it because they can afford to (there was a first edition whose range of sourcebooks was never completed), and they are even releasing the PDFs for free in an attempt to garner more interest for the setting. The art direction is top notch.