Dr. Wily stage: Easy extra lives
On the first Dr. Wily stage, after the check point there are six pipes. Two of them have weak respawning enemies. Use Jewel Satellite and stand on top of the first set of pipes. You will occasionally get extra lives and a lot of bolts. You can use this trick to replenish lives lost from the puzzle that is up the ladder. This also helps when completing challenges. Note: This requires a lot of time.
Hornet Man stage: Unlimited screws
You will need the Jewel Satellite in order to do this trick. In the beggining of Hornet Man's stage, move to the right until you reach the first ladder. Without destroying the potted plant robots, activate the shield and stand on the second platform in between both the robots. If you remain standing there, the missiles will be destroyed and the screws will automatically land on Mega Man. This also increase your kill count for your achievements.
Weapon recommendations
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.