As Unload mentioned, I'm an admin on the Taleworlds forum (username Merentha) so if you've got any questions, I'd be more than happy to answer them. Unload described the game pretty well, I think.

Basically, you've got an indie RPG intially developed by a Turkish couple who decided to gain money for continued development by selling their betas at a discount. When I bought the game, back in v.632, it cost me about 10 USD, and that purchase entitled me to all future versions of the game. I've been playing all the versions since, and watching them update and improve the game has been fantastic.

Gameplay is very simple and highly intuitive. The meat of the game is the combat system, which is simply phenomenal. The highlight there is the mounted combat. Some might compare the basic concept to Oblivion's, but it exceeds Oblivion's in almost every way. Instead of basing your attacks on which way you move, it bases it on a very, very quick movement of the mouse. (For those worried about Die by the Sword's flailing about, don't worry, its much simpler and better). For instance, to slash downward, I'd move the mouse slightly upward and left-click. Blocking works in a similar manner. To parry high? look up slightly and right-click. (The game defaults to right-click auto-detecting which way to block, which makes it substantially easier. For those looking for a serious challenge, change it to manual block. It will practically force you to use a shield or get very, very good). Shields will cover all four target directions, but at a cost to the shield's "health". Now, this excellent starting point (and its so wonderful you wonder how every other developer to date has missed it) is improved by the large-scale combat and horses. The game defaults to a maximum of 72 troops on the field at a time, but a basic mod can increase that to whatever your computer can run. I've personally fielded 350, with the graphics settings maxed, with no slowdown. Those willing to sacrifice beauty for gameplay can obviously top that with no problems. The horse combat is similar to the unmounted, except you're obviously on a horse. This allows you to ride in, slash, and ride out with much less risk for yourself (or, if you're a real coward, you can be a horse archer and not even have to do that. ) You can also play a lancer and simply ride down enemies with a lance, hitting them for essentially a guaranteed one-shot kill. When your horse is killed, you're thrown from in and seamlessly continue the battle on foot. Your army can be controlled with a decently robust system of commands, though it admittedly could use a few refinements. You can order your troops to charge, follow, halt, widen/close ranks, fall back/advance and so forth. With a few mods, you can also order formations. Finally, you can order men to do different things based on weapon. One common, yet very effective, tactic is to order your cavalry to follow you and your infantry to hold position on a hill with archers in front. Before the point of contact, you order your archers to fall back, your infantry to charge, and you lead the cavalry into the side of the infantry scrum. For those drooling about multiplayer, however, I must disappoint you. It remains a single-player game at the moment.

That's the combat system, but its not all of the game. On the world map, you can roam around and recruit troops, raid villages, visit towns and get basic quests, and so forth. Here's where the game's indie roots shine, since a lot of the worldmap, while well done, doesn't quite hold up to the combat system. Its a bit simplistic, but does what it needs you to do: get troops and opponents to fight. Essentially, your soldier is plopped down in the middle of a wartorn country, with five unique factions. They dynamically (and by that I mean semi-randomly) go to war with each other, launching large warparties led by lords who roam about the country-side trying to take each other's castles and raid their villages. Later, you'll be able to do this yourself too. There are also various types of bandits, deserters, and caravans wandering around for you to defend, extort, or slaughter, as takes your fancy.

One of my favorite features of the game is the general openness of it. Story? None. Really awkward and counter-intuitive morality system? None. Mandatory anything? None. Want to play a skirmishing bandit and raid caravans for a while? Have a blast. Viking raider? Infantry leader? Norman lancer? Kingmaker? Any of the above are easily possible, and that's in the core game alone. One of the Taleworlds team's biggest accomplishments and wisest moves, in my opinion, has been their love and support of mods for their game. v1.011 recently came out, so the full breadth of mods isn't yet available, but they certainly will be.

And, finally, as Unload again said, the demo's free. Play it and see what you think. If you like the combat system, which you'll easily get a feel for by the time the demo ends, its probably worth a buy. A lot of the negative reviews did focus on the graphics (which aren't top notch, admittedly, but the game was built ground-up from a husband-and-wife team who only recently hired other graphics artists. I think it looks more than fine, and occasionally beautiful, but I'm also not one of the people who demands Crysis-level graphics in everything I play) Siege combat can feel a bit clunky at first, too. The worldmap is also a bit simplistic as well. Make no mistake: you're not buying a huge RPG with a story, villains, and so forth. You're buying an amazing sandbox combat engine with fantastic mod support and a dedicated group of skilled modders.