Ippun!
What exactly made this game so cool? Well, it's hard to pin-point, but I would say mostly that game has "style." Being a game about samurai's, it borrows a lot of it's trademark action from samurai movies from Akira Kurosawa and samurai fiction like "Musashi." For instance, when two players strike each other at a same time, there will be a moment's pause, then one of them falls over. Classic. Other simple touches like getting the last strike onto an opponent and watching him stand motionless, only to see a fountain of blood spray out of chest in old-school samurai fashion, or the gruesome evisceration when a character's top half slowly slides off his lower half. Not to mention the game's announcer who speaks in purely in Japanese, remarking excitedly each character's name, and the dramatic "Ippun!" when a round has been won. It's just friggin cool.
The backgrounds are huge, with the areana scaling out to 3 times the normal screen size, then zooming back in when the action gets tight. There's plenty to see and a lot of interesting details in the enviornments. The character animations are spot on and unique to each character. Powerful but subtle touches such as Haohmaru taking a swig from his gourad and spitting the contents onto his sword, or the way Cham Cham and her monkey pound their chest in unison before a fight... these are the little things that add so much atmosphere and personality to the characters, it's hard to imagine another fighting game injecting so much style and character into each of the players.
Another suprise is that a lot of these characters are based in dramatic history. Haohmaru bears a strong resemblence to the unforgetable ronin "Musashi", who wandered the country side in the years following Sekigahara and rose to fame over history through the retelling of his adventures and encounters. Ukyo being "Ganryu", Musashi's greatest nemesis in the story of Musashi. Jubei, an eye-patched ronin in the actual story of Musashi who bore the same name and was known for his double-sword fighting style. In addition, the level that Ukyo and Haohmaru have are the same stage but set at different times. This is no coincidence, as it's a reference to the actual story line where Musashi and Ganryu faced each other for their final bout.
This game isn't for everyone. It certainly isn't a "button masher" like Street Fighter. It's played a little more like chess, where each of your moves have to be timed well and done with purpose. Luck can play a factor in winning, but skill and anticipation is key to being consistently victorious. It's a difficult game to master, and it's fighting dynamics don't fit with today's button mashers like Soul Calibur.
Anyway, I'm a bit biased when it comes to Samurai Showdown 2. I've spent countless hours playing this game in the arcade, and I have a lot of positive memories about it. It was a really great shock to see it on XBLA, and how well it has been preserved. An instant download for me.