I got this release day and I'm a bit surprised no-one mentioned this before today (and don't ask why I didn't bring it up).
It's an aciton RPG, you earn and spend experience to increase your characters stats, but the actual play style is a 3rd person action game, much like Zelda OOT.
Your actions effect how your character turns out, get hit alot and he get's scars... Eat alot he get's fat... stop eating and he get's thin.... boost your strenght and toughness and you get beefy.... stand out in the sun alot you get tan.... only come out at night you remain pale.... you get the ide.
Fable, much like Black and White, has a morality system that effects not only how your character looks but how other react to you. Do lots of good deeds and your characters eyes get lighter, his hair turns blond, you get a nice shiny halo, a shaft of light beams down on you (or is it up from you?), and eventually you'll have butterflys hovering around you.
Got the Evil route and you get dark, eyes turn red, you attract flies, you grow horns , and a red glow starts to come from you.
The game earns it's M rating from a few places, 1st being combat (the worst of which is decapitation, and is pretty tough to do early on). There is some language, including a rude gesture and the ability to "cuss" as you become more evil. There is not only marriage, but also sex in the game, HOWEVER, nothing is ever shown. I don't think you could even call the voiceover durring the blank screen cutscene to be "exciting," I actually found it quite amusing as my one wife (yes, you can marry more than one) called me "norty" (it's a brittish game, voices and all).
Speaking of marriage, you can marry some of the men in the game (and your character is a male), hence there is essentially Gay marriage available, but it's not as common, you can't marry just any man (where as most of the women will eventually fall in love with you as soon as you enter the town depending on how you've been playing). My understanding is that you actually are better off with a woman as you get a dowry, something which you won't get marring a man.
Religion is mostly minimal, and seems to focus mostly on two "gods," a good "god" named Avo and an evil one named Skorm (or something close). Each has a temple somewhere in the world, though I missed the evil temple the first time though (wasn't looking for it either).
Lionhead gave alot to sandbox with in the game, including the fishing thing (which is quite fun to do), the option of doing some of the side quests, the whole marrying thing, beging able to make money by trading (Fable works off a Supply-and-demand system as well as your Guile stat which helps lower the cost of buying stuff).
The most offensive stuff to Christians will/would be the things related to being evil and the fact that they allow you to woo and marry a man. Poligamy (sp?) is allowed as well, but only one wife per town (and no moral judgement is made on you reguards to that, it's not considered either Good or Evil by the game). The thing about all these is that they are player choice, chose not to do them and they'll never come up in the game.
The game is short for an RPG, people have been giving it playtimes from 8 hrs up to 40.... alot has to do with how much time you spend running around and how much time you spend trying to get through the main quest story. Since there are quite a few ways to play your character (aside from just the good/evil thing), you can always replay... or just play around, it's very possible to own just about all the towns if you work hard enough at it (and don't mind getting your hands a bit messy
)
Oh, and in addition to the physical changes your character goes though depending on your play style, you have the option of what you wear, how you style your hair, and what (if any) tatoos you place on your body. All of these items change how the NPCs react to you (you have a scaryness factor as well as an attractiveness factor to each of the items).
Overall I'd say this game is awesome, it's a great game, even at $50 (unless you get bored very easily, which means that most games won't hold your attention). The game does have an M rating, but I don't believe that most people would find it nearly as offinsive as a game such as GTA3, most likely on par with Halo for violence levels, and there was far more language in Halo than Fable.
There's alot I haven't even touched on, and I'm sure there is quite a bit that I haven't even seen (lots of small details abound, including the fact that your character "squints" while looking toward the sun). Any more Questions and I'll be happy to answer (though I loaned it to a friend of mine when I couldn't play for a while due to the power being out at my house).