I don't know about best but I definitely know one of the hardest. Street Fighter II has you beat all 12 characters then you get to wizard mode and have to beat all 12 characters again except on the current ball only. If you drain then you have start from the very begining just like pressing start. I have gotten 11 characters 3 times in wizard(champion) mode but haven't gotten all 12 for the 500 million yet. Someday