So, in A**holevania, the boss battle there is Mr. Hyde. Now you may die a decent amount of times, which is why this guide was made. So, you will want the Super Scope upgrade for the Nerd. If you can't get that, I reccomend using the B.S. Man. If you don't have him, leave the level, go to Beat It and Eat It to unlock him (You will need to play as Mike however).

Anyway, to defeat Mr. Hyde, you will need to dodge his fireballs. As I said, you will need the B.S. Man, as he is the only playable character that can double jump. You will need to time it just right, or else you will be hit. Watch out for Hyde jumping, jump enough times yourself, and Mr. Hyde will be stunned while in his Jekyll form. Use the B.S. Man's attack to drain his health. Wash, rinse, repeat, and you should have one less pain in the butt when it comes to levels!