According to the Xbox Live Arcade sales estimates, you can add another 120,000 purchased copies to that list....Which will definately help sales.
As everyone else has said, it's a fantastic RPG/Bejeweled 2 hybrid. Enough RPG elements to take away from the generally boring, ultra-casual element of some of the puzzle genre.
The only "issue" with the game (and such a low score) is that it's definately NOT complex, or insanely perfect by any sort of standards. Luck has a huge part in the game, and sometimes the CPU can feel like it's "cheating", stringing together lots of 4 and 5-combo chains, and damaging you alot in just a few rounds.
Sales wise, the issue is that I believe the game debuted at $40. Wayyyyyyyy too expensive. The game is meant as a sub-$20 casual pick-up game.
As a X360 owner, we get it at the stealing price of $15 USD. Definately a game you want to pick up for the DS or Wii at the $20 range.
Probably one of the best "must have" budget games of the year. Definately underrated, unless you get into a good Puzzle Quest circle.