The DS is rife with puzzle games, RPGs, platformers, and tests of mental strength, but you don't see a lot of hardcore action games on the system. It would seem that those tiny buttons simply aren't made to withstand the furious button mashing that such games require. Despite this, Team Ninja has found a way to bring its frenzied and notoriously difficult Ninja Gaiden series to Nintendo's portable machine.
The solution to bringing the game to the DS might seem obvious (but you'd be forgiven for doubting if it could actually work)... make the game stylus-driven. We're not talking a few stylus commands here and there; the entire game (save defensive maneuvers) is controlled via the touch screen. It doesn't sound like it would work well at all, but Dragon Sword does a fine job of walking you through the control scheme, and after slashing an enemy or two, it feels perfectly natural.
Once again, you control Dead or Alive's top ninja Ryu Hayabusa, as he struggles to collect the eight spherical Dragonstones in a plot that totally doesn't at all kinda sorta sound a bit maybe like "Dragon Ball." At all. But who's really concerned about the plot when there are a ton of demons to slice up? Just point to a place on the screen and Ryu walks over to it. To attack, simply drag the stylus across an enemy and Ryu dashes over to it and delivers a quick hit. Tap on the foe and Ryu tosses a shuriken at it.
To jump, just make an upward slash with the stylus. Once you're up in the air, there are a couple more powerful moves that you can pull off, including a damaging downward thrust and one where you fly across the screen. Perhaps the most powerful move is a charged maneuver that requires you to rapidly move the stylus back and forth to build up enough energy to unleash a blast that damages everything on the screen. Ryu is rather vulnerable while the charge grows, but if you're fast enough with that stylus (and don't mind a little carpal tunnel) you can pull the move off repeatedly.
Making somewhat less effective use of the stylus controls are the Ninpo magic attacks. These special moves are activated by tapping an icon in the upper-left corner of the screen. Then, you must trace a symbol that appears on the screen to activate the power. From there, each spell takes effect. Halting the action to make you pointlessly draw a symbol adds nothing to the gameplay and takes you out of the battle. The game makes such great use of the stylus that gimmicks like this aren't necessary.