This patch is meant to make the game a bit easier and less frustrating. 
Applying this patch to Mega Man World 4 will make the weapon energy of all weapons restore fully whenever a life is lost. 
This mechanic is officially applied in Mega Man games for the PS1 and later. 

Situations where this primarily affects the game:
- Bomb sections in Wily Stages (Ballade Cracker required to make them explode quickly enough)
- Boss battles (running out of weapon energy)