This game is the reason XBLA is so awesome.
In all fairness, this is the first game of it's type I have played, but I was immediately sucked in by how great it is. I like turn based role playing games, and I like puzzle games. Of course, puzzles can get a little boring after a while, and TBRPG's get a little boring since you spend a lot of time watching your opponent move. This game changes it up often enough so the puzzles stay fresh, and instead of the random roles of TBRPG's, you get the chance to influence the roles in a way that is challenging and fun. Of course, you can still get destroyed by a low level enemy if it gets a great board drop, but as you get better at running the board, you can plan for bad bounces, and nothing is more satisfying than beating a challenging opponent by using your noggin to do so. Pick it up, and you will wonder where the hours went. Great game.
And, on a side note, I have been so damn impressed by XBL download games lately that the last 6 games I bought for my Xbox all Arcade.