Imagine Knights of The Old Republic meets Crouching Tiger Hidden Dragon and you'll have the jist of Jade Empire.
BioWare's idea was whatever your Character does, effects the world around you. Simple Right? Surprisingly it's not. Many game companies have tried giving it a shot, with mixed results (see: Fable). And while BioWare might not have perfected this yet or hardware limitations have stopped them short, they have made some Great Steps Forward.
The first game BioWare attempted with this character involvement idea was Star Wars: Knights of The Old Republic (KOTOR). The game was so groundbreaking because no one had seen anything like it before. In Game NPC's would actually react to you differently depending on whether you were good or evil.
It was on that bases that BioWare made Jade Empire. Sent in a World of ancient Japan, which ironically is one of the first RPG's to do that, you are a simple trainey at a Japanese Dojo. Until one day it is attacked and everyone either captured or killed aside from yourself. Spinning you off into an adventure to find your old master and rescue him. The story is one that might sound shallow, but is actually quite expansive and full of twists.
On your way to finding him you meet all kinds of characters and in a style very much like KOTOR you communicate with them and depending on what you say will effect the people's reaction to you. You can choose to be kind to everyone and run the risk of being tricked or you can be the one tricking everyone else. The openendedness of the game is just as appealing in Jade Empire as it was in KOTOR. Maybe even moreso.
The battle system is akin to KOTOR as well, except now it's realtime attacking instead of you selecting a command and watching your character perform it. Jade Empire is almost a fighting game in that sense. You can keep hitting the punch button if you want or you can combine different attacks to perform special moves. It's much more enthralling than KOTOR and the variety of characters and weapons keep the fighting interesting all the way through.
Speaking of weapons. The fighting system is divided into different "stances". Some of which are weaponless stances and some of which are with weapons. Depending on what type of monster you're battling, different weapons are more useful. While the staff might be slower than the sword, it does have a much longer reach and can hit multiple enemies. The long sword might be faster than the staff, but it has a shorter range. Two daggers might be the quickest fighting style but it has the shortest range. Same goes for weaponless fighting as well. Some stances will give you lightning fast weak attacks while others are slower and more powerful. And they even throw in Drunken Boxing for a quite slow but very fun fighting style.
Jade Empire will run you about 20 hours to complete the main story. A little less if you don't do any side quests. A little more if you do them. Which I'd recommend. Part of the Charm of Jade Empire comes from just traveling the world and interacting with people. It's not just about getting extra weapons and better items. It gives you plenty of storyline points and as well as the world just being fun to explore.
Is Jade Empire an instant classic? No. It's not. Mainly because some of the character building system has been seem before in KOTOR. Had KOTOR not been released before Jade Empire, BioWare would have a game here that would blow people away. As it stands the storyline, battle system, and the interactive and interesting world still make Jade Empire a very GOOD, FUN game. If you've never played KOTOR before, you'll be blown away by this game. If You've played KOTOR before and enjoyed it, do not shy away from Jade Empire. You'll be missing out on a very well done RPG.