Samurai Warriors 3's mysterious Nazo no Murasame-jou mode, based on Shigeru Miyamoto's Famicom Disk System game, was not included in the demo for the Wii game, nor were any new details available. In the absence of that novelty, Samurai Warriors 3 is your basic Warriors game -- which is to say that it is purely about mashing buttons to unleash combos against hordes of soldiers. What it adds to the formula is an ample character selection, including around 40 new and returning characters, and some new, super huge combos. And, of course, it adds being on the Wii, which is pretty important to a certain segment of the gaming population (the segment that owns Wiis). That's not to say that this is Samurai Wagglers (that was the poorly-received Samurai Warriors Katana) -- this game is traditionally controlled, and will even be bundled with a specially decorated Classic Controller Pro in Japan. Of course, with Nintendo not really talking about the Pro, there's no way of knowing whether the game will have a similar bundle upon its 2010 release in North America and Europe.
The "kaiden" combo is an even bigger attack than the standard "musou" attack. When you launch this attack, a short Final Fantasy-style attack cutscene plays, and your character does something ridiculous like hitting the ground and damaging everyone nearby with some kind of shockwave. There's also a technique called "Eigi," which uses the same energy meter depleted by the kaiden combos, which makes your character temporarily invincible during normal attacks. This is designed to allow you to put together uninterrupted combos, sort of like Street Fighter Alpha 2's "custom combo" system.
What's new for the "next-gen" version (and therefore new new, not just new to people who didn't play the PSP game) is the way your "Strikeforce" is handled. In the PSP game, you could get help from up to three friends in local multiplayer, but if you were playing alone, the game was just really hard. Now, when you don't have anyone joining you, your Strikeforce is made up of three AI dudes who help you get through the crowds of soldiers and giant monsters. You can use simple button commands to direct them to attack strong enemies, protect you, and other such behaviors. The other big new feature: online play! Your Strikeforce can now get together online instead of just locally, something that strikes me as a genuinely novel feature in a seasoned series.