Ign have done a "hands on" for the demo:
"Different from the past demo versions, the new retail demo appears to start off right at the start of the game. Since you probably hate it when anyone spoils your Zelda, we'll skip the details and get to the point. Link, in search of Tetra, arrives on an island and falls in the company of a Navi-like fairy. You're told to head to the nearby port village, where it appears sea-travel awaits Link once again.
Nintendo wastes no time getting players into the game. You first start off by solving a simple puzzle in order to get Link's sword. This puzzle involves writing a number on a board directly with the stylus. I was able to input a "7" numeral character to solve this puzzle, in place of a kanji character. Of course, importers may want to prepare themselves in case later puzzles require actual Japanese inputs.
Sword in hand, you're able to lead Link into a forest, on your way to your first dungeon. The forest has lots of enemy targets, which you can take out using the stylus-based combat controls. Expectedly, the game also seems to feature plenty of foliage to chop down, with larger trees joining the shrubs Link has been cutting down since Link to the Past.
We detailed the game's stylus-based controls back in our E3 hands-on playtest. However, for those who are just tuning in, we'll reiterate. This game is controlled exclusively via the stylus. You move Link and target enemies by pointing, and execute special attacks by sliding. Buttons are used for shortcuts, like toggling the map from the top screen to the bottom, although these can be performed with the stylus as well.
The Touch! Try! DS kiosks are programmed to make you stop touching and trying after just 10 minutes, so I was only able to sample the controls via just a few quick fights. I did manage to replay those 10 minutes over and over again, though, and have to admit that while initially skeptical, I've come to love controlling Link via this new control scheme. Combat is fast and fluid, with Link connecting attacks between different enemies. The stylus also seems to be better suited for some moves, like picking up and tossing objects.
What's really telling is that my impressions are so favorable even though I wasn't actually using the stylus. The retail kiosk I used was missing the stylus, so I had to use my pointer finger to play. Even though the screen was somewhat blocked off due to my fat finger, I was still having a blast just moving Link around and slashing at things. With a proper stylus in hand, the experience should be even better!
Nintendo seems to have embraced the stylus completely for this latest Zelda game, rather than going the safe route that most third parties take and offering the option for "standard" controls. As Link advances on his quest, the stylus should come even more into play, with the boomerang requiring that you draw a trajectory, and sailing requiring that you plot out paths on a map. And, of course, there's the ability to jot down memos on the map directly. This will presumably help out when dealing with a particularly tough dungeon.
In addition to the stylus controls, I was a bit worried about the downgrade in visuals from the GameCube to the DS. While the game doesn't have the clean visuals of a GameCube game, it does retain the overall look of its controversial predecessor. On top of some solid cel-shading, Nintendo has packed plenty of detail and animation into the visuals, and even managed to get 3D displaying on both screens during cinemas, a trick that only a few DS games have used so far.
This could be one of the best looking DS games yet.
Screenshots and online videos don't do the game justice. See it running live on the tiny DS screens, and you may have to look twice to convince yourself that this is a DS game.
It was tough to force myself away from the demo kiosk even after playing through the same area of the game multiple times. The wait for the Japanese version of Phantom Hourglass is just a few days, but it's going to be painful. You'll have to wait even longer for a true localized version, but we'll be sure and provide full impressions once we have the final import in our hands."
So sounds like its a demo that you can only play at the kiosks. I'm guessing you can only get it from having a dump of the actual cart? Doesn't sound like its a download to the DS and play demo but then I could be wrong.