Sudoku is sudoku, regardless of where you play it. The popular pencil-and-paper game (or pen, if you're hard like that) has gone digital a billion times over in various free flash forms, and now there's getting to be a glut of them in the portable market as well. Dr. Sudoku, however, is the first for the GBA. Since sudoku isn't going to change from one platform to the next, it all really comes down to what sort of interface and features the game has. And Dr. Sudoku has a pretty solid feature set.
Confused by all this sudoku talk? OK, we'll back up a bit. Sudoku might look like a math version of a crossword puzzle, but it's really all about logic. There are simple rules that determine where a number can legally sit on the sudoku grid. Each puzzle starts you out with a few numbers filled in, and you use those to deduce where the other numbers go. Like most good, addictive puzzles, it's easy to learn the ropes. If you're new to all this, Dr. Sudoku has a brief tutorial that should get you up to speed.
It also has a number of help devices that practically make you feel like you're cheating. You can select any number from a side menu and lines will extend from that number's positions, effectively crossing out any areas where those numbers couldn't be placed in other spots on the grid. It's very handy, but it really just makes things too easy. You can also write notes in some of the squares to denote possible numbers for each square. The controls in the game are pretty streamlined, but, really, a D pad and four buttons just isn't the best way to play sudoku.
On the options side of things, Dr. Sudoku is a pretty stout package. There are a thousand puzzles in the game, but you can also create your own sudoku puzzles and save them to the cart. This would also let you read a puzzle in the newspaper, enter the given numbers you see there, and take that puzzle with you without having to be that creepy guy who always has a newspaper under his arm. And if the newspaper puzzle has you stumped, Dr. Sudoku can automatically solve that stuff. But really, aren't you only cheating yourself? Consider the game's repetitive music as your punishment for taking the coward's way out, sudoku-style.
If you love sudoku, you're probably already playing it for free somewhere else. And if you're looking for a handheld version of it, get one with touch-screen support. But if you don't have a DS or a PDA or something, and you're looking for something you can tote around in your Game Boy Micro, Dr. Sudoku can most certainly help you out.