Heh heh, it's funny 'cause it's true
Wonderful job, you've truly captured the true meaning and essence of the game/TV show/manga Yu-Gi-Oh.
No other flash on Newgrounds more perfectly shows what an anime show is like more than that one. A repetitive moron of a main character trying to solve all the worlds problems by battling people with fake monsters on cards.
You were perhaps a bit too repetitive in the way that basically all he said was "card maatcchh", but I suppose that did add a little to the humor. Maybe if you had just slacked off on it a little it would've been better. Not that I'm dissing it, I thought it was great.
Otherwise, I couldn't really tell you how to make it better. The backgrounds were great, sound was great, style was great, it was highly hilarious, it had all the stuff it needs to make a great flash.
Excellent work, keep it up!