For the most part, it seems to work surprisingly well. Constructing a fast-paced action game entirely upon stylus strokes might lead you to think that victory hinges on furiously scratching your screen, but Dragon Sword's inputs are distinct and responsive enough to render battle a calm and intuitive affair. Well, as calm as you can be when being assailed by clawed freaks, disgruntled dragons and, in one instance, a steady stream of menacing boulders.
Movement is handled on the DS (which is held like a book, á la Brain Age) by simply pointing to your intended destination -- think of it as series protagonist Ryu Hayabusa chasing after a mysterious obelisk looming above the prerendered environment. Flicking the stylus upwards will initiate a jump and a downward stroke immediately afterwards performs a vertical slash. Horizontal strokes yield standard slashes, while a quick tap on an enemy sends a shuriken in its direction. A more complex move like the Izuna Drop translates to a combination of these primary motions, with a few horizontal slashes followed by an upward stroke and finalized by a downward smash. Blocking is the only function to be assigned to a button -- any one will do.
Obviously, the greatest loss suffered here is in terms of precision. Compared to the console equivalents, Ryu's move list has been considerably simplified and softened, almost to the point where it feels indirect. Accordingly, the enemies are much quicker to dispatch now and while that may imply a "dumbing down" of the gameplay as a whole, it's really the best match for stylus-driven controls. They feel simple, responsive, and despite the lack of relative complexity, exceedingly effective. As fans of the series will note, destroying fiends with deadly efficiency is one of the primary sources of satisfaction.
Ninja Gaiden: Dragon Sword doesn't disappoint in terms of visuals, though you might consider the use of prerendered backdrops as a form of cheating. Regardless, it does leave the DS with more room to render some fairly detailed character and enemy models, all brought to life with some of the most fluid animation we've yet seen on Nintendo's dual-screened device. The fixed camera angles seem to present a good, distant view of battles, though running further into the background occasionally results in one awfully tiny Ryu. Off-screen attacks are a concern too, but in the space of the entire demo, only an unexpected boulder managed to surprise us from beyond the field of view.
Though the appearance of oddly murderous rocks was confined to a single instance, the TGS demo does hint at the presence of "obstacles" throughout the game. They deserve the use of quotation marks largely because it seems these impediments are excuses to expand and use Ryo's repertoire of magic. When a giant spiderweb blocks your progress and becomes strangely immune to your sword attacks, you'll be reminded of the need to summon a rolling ball of flames (amongst other Nin-Po, no doubt), done by tapping an icon in the top right corner of the screen and tracing the displayed symbol -- successful strokes result in magical mayhem.
Thankfully, this attempt to alter the game's pace is likely to be the clumsiest aspect of Ninja Gaiden: Dragon Sword. Its elegant implementation of stylus controls make it a highly accessible action title without dulling Ryu's blade.