The graphics, at least in terms of Blackberry apps are actually pretty decent. The game uses 3D rendering that provide smooth transitions which add to the overall playability of the game. Not the best graphics available but there decent enough for a $6.99 game.
Here's a look at the graphical interface. As you'll notice all of the controls, such as the power bar for throwing your darts, the scoring table and wind meters are all well placed in order to make the most out of your small mobile display size:

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I started by playing the game in single player mode against the computer and I must admit that the computer actually offered some challenging gameplay which didn't leave me feeling that the gameplay was lopsided. I also played with my buddy in multiplayer mode on a single device (we just passed the device back and forth to one another) and in Bluetooth sync mode from my Blackberry Bold to his Blackberry Pearl. The bluetooth sync capability worked quickly and we never lost our connections to the game as we played. Essentially there is plenty of gameplay options for you and your friends to experience.
The actual throwing of darts gets much easier after a few games, however when first starting out I had some issues figuring out where to throw in certain wind conditions and the power I needed to use. This part of the gameplay is fixed with some trial and error. I attribute it to playing a game of golf, you play 3-4 times and all of a sudden your hitting birdies and pars all the time. Yet while the gameplay gets much easier it can still be challenging, especially if you're friends have mastered the controls as well and you play in multiplayer mode.
There is also a dart chooser mode which lets you choose between certain darts with certain functions: fire, laser, bomb, splitter and nuke darts to be exact. For example you may use a certain dart where you just need to throw it and let the computer take care of the rest. See the screen below:

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The game also offers a tournament mode which increases in difficult as you play and challenges you to win multiple levels in order to be crowned the champion. You even get a trophy room to display your accomplishments. The trophy room is basically a fance way to display your high scores with a unique layout.
Finally, you can choose a bunch of different backgrounds from a backyard to the forest to the moon.