First of all, I have a PS2.
The Power Punch is where the punches look all blurred and have SPECIAL knockout power.

I just can't do it. haha

The booket says to...
Tap R1 then press either square, triangle, x, or circle (It depends on the boxer.)

The fighter I chose was Rocky. But no matter how I tap R1 and the other buttons. And whichever speed or hold them or whatever I still can't do the Power Punch thing.

How in the hell do you do those devastating Power Punches!?!

The computer does them on me all the time, and thats how they end up knocking me out!

I just bought the game and so far the first Rocky game is better.

Man you press r1 and then half a sec later press the button, with apollo its square and with rocky i think its circle, got the game today and its not bad.