I tried to play the first one, but I came away with the impression that this fan game is hard as shit and is only designed for Mega Man sweatlords and speedrunners.
Yeah I think it's an add-on. There's like a mode where you instantly die if anything hits you because we know only hardcore guys play these Mega Man fan games, though I think Zero normally doesn't take damage from anything unless he's attacking (he'd just block everything).