This game is also available on GBC.
When your opponent's life is blinking red, charging Back (two seconds) to Forward + Y. Then press Forward, Forward + Y, L(3), Forward, Forward + L, L(3), then press Forward(2), X for his Ultra combo and do about 28 hits. When the opponent falls, press Forward(2), Y. If you did a Combo Breaker, this should do about a 31 hit Ultra.