Gunstar Super Heroes – Platform: Gameboy Advance

The Easy Supercharge:
There indeed is a way to quickly fill up the weapon gauge, that allows
you to do a supercharge attack. Deflect enemy fire with the sword attack
with the B button. They will drop green items you can pick up (press B +
Down ) that will quickly fill the weapon gauge. When the gauge is flashing
you can do the supercharge attack by pressing R, R.