In Mega Man 2 you unlock the weapon most associated with Mega Man, Metal Blade, by defeating Metal Man. It might seem like a surprise that you don't start with Mega Man's signature weapon but astute players will notice Metal Man uses Metal Blade too. Mega Man learned it from him!
Stole this from ace attorney twt , what's your favourite detail in Megaman ? It can be ANYTHING and in any series , as long as it's something you don't immediately see