Use the following weapons to defeat the corresponding opponent.

Galaxy Man: Use the Mega Buster.
Jewel Man: Use the Black Hole Bomb.
Plug Man: Use the Jewel Satellite.
Tornado Man: Use the Plug Ball.
Magma Man: Use the Tornado Blow.
Hornet Man: Use the Magma Bazooka.
Splash Woman: Use the Hornet Chaser.
Concrete Man: Use the Laser Trident.
Wall Shooters: Use the Mega Buster.
Giant Machine: Use the Laser Trident.
Blob Monster: Use the Black Hole Bomb.
Dr. Wily part 1: Use the Mega Buster.
Dr. Wily part 2: Use the Mega Buster.
Dr. Wily part 3: Use the Plug Ball.

Try the following Boss order and recommended weapon.

Splash Woman: Use the Mega Buster.
Concrete Man: Use the Lightning Trident.
Galaxy Man: Use the Cement Shot.
Jewel Man: Use the Black Hole Bomb.
Plug Man: Use the Jewel Satellite.
Tornado Man: Use the Plasma Ball.
Magma Man: Use the Tornado Blow.
Hornet Man: Use the Magma Bazooka.