I am kind of mixed here . . .
You are enrolled in a school for duelers who want to improve their skills and decks. Your goal is to become the top student at the school by improving your deck and battling against a number of different people. The game runs on a calendar system that counts through the days and prevents you from doing too much on one day.
One of the problems with this game is that as the card game becomes more complex, playing the game on the GBA becomes more difficult. There is too much information to keep track of and navigating through all of the screens becomes a little tedious and annoying. Plus, if you press a button at the wrong time, you can completely screw up what you were trying to do.
I think that the graphics are only a partial improvement. The battle screen is a little difficult to keep track of and the battle animations are fairly poor. They are only slightly improved from the original games on the GBC.
I think only someone who is already familiar with the Yu-Gi-Oh Universe and has a lot of patience can get anything out of this game.