Buku Sudoku is the sudoku game to get on XBLA... because it's the only sudoku game on XBLA.
There's not a whole a lot to Buku Sudoku, but honestly, how can you really cram a lot into a game that's pretty much nothing but logic puzzles? The game comes with 1200 puzzles with two puzzles packs consisting of 1200 more puzzles each currently available for free, and they're broken down into 6x6, 8x8, 9x9 and 12x12 categories with easy, medium and hard difficulties.
There are multiple themes that you can use to play Buku Sudoku with, except for the 6x6's, which is a toy theme that cannot be changed. Such themes having you playing on Japanese tea tables, note pads, newspapers and display monitors. It would have been nice if the game came with a few more themes, and had them a little more interactive, maybe with some animations here and there.
Playing Buku Sudoku is pretty easy. You move your cursor around with the left stick, while choosing what number you want to select within the cell with the right stick. There are several other control schemes that you can play around with if you like, even some that let you play one handed. It's also rather easy to identify mistakes, because if you have two conflicting numbers within a column, row or group, those numbers will be highlighted. Once you get everything correct in a column, row or group, there will be an outline that will form around it indicating that it's finished. Sure beats playing sudoku on a piece of a paper, then realizing that it's all screwed up once you fill in the last cell.
There are a few multiplayer modes that you can play on XBL if you're fortunate to know someone else who has this game. You can play the game cooperatively, with each player having their own cursor on the same board to fill in their own numbers with. You can play one on one versus, or you can play team versus, which has players trying to solve their own puzzles before everyone else and removing numbers from their opponents' puzzles.
The presentation is simple, yet effective. The graphics are clear and crisp. The music at first is cool, but tends to get a bit repetitive. It would probably be in your best interest to use a custom soundtrack if you plan on sitting down to play this game for more than a half an hour.
Buku Sudoku clocks in at 800 MS points. It may seem a bit much, considering there's really not much to the game, but keep in mind that you're getting 1,200 puzzles with two free puzzle packs already available. You'll definitley get your money's worth if you really love sudoku.