Several years ago, Mega Man creator Akira Kitamura revealed that he initially wanted Mega Man's appearance to change whenever players equipped a different Weapon. Although this idea wasn't fully realized until Mega Man 11, the concept has been there since the very beginning, owed in part to a little television program called Ninja Captor.
In an 2011 Rockman Maniax interview (translated by Shmuplations), Kitamura said:
"In the beginning, I imagined a character like Mega Man equipped with some kind of weapon, but when you transformed, your whole appearance would change. You know that little protrusion on the top-front of Mega Man’s helmet? When you changed weapons, it was supposed to change like the Ninja Captor character’s helmets, and show a little symbol depending on the weapon’s element (fire, water, lightning, etc)."
Unfortunately for Kitamura's team, they weren't "allowed to use symbols like that". They were concerned about infringing on Ninja Catpor's copyright, in other words. Instead, programmer Matsushita-san came up with the idea for Mega Man's color changing mechanic; a trait that has followed the blue bomber ever since.
Today, we can look back on Ninja Captor with posterity. Thanks to Toei's newly launch "Tokusatsu World" YouTube channel, we can watch the show with English subtitles for free and legally. I've embedded the first episode above.
If you've never seen 70s tokusatsu, you're in for quite the treat!