I just dont get the "idea" of a darts game, thats on a pc.
Its far worse than say a pool game. Theres no "life" to a 2D dart board seen from the front.
The reason a game like angry birds works, is because of the side view (this doesnt work for darts, since the principle is to hit the center, and you cant with something seen from the side). If you think about it, Angry birds is just a "fun" way to make a darts game for a pc, and it works, its sold millions.
If... you wanted a "real" darts game I guess..
You could make a 3D darts game, where you saw the avatar and the darts board from a angle'd view (so you can have a sense of the center of the dart board) , possibly with a cam following the dart (once thrown) or some such. Unless you do something like that however, its gonna end up one hellva flat experiance.
Want to play Darts? do it in real life (thats one of the beauties of darts, its easily accessable and doesnt take up to much space).
Its not like a raceing game, where speed/location/other drivers/cost of car/reclase driveing ect are a issue. So the only way to really experiance such a thing for a "normal" person is from a game.