Looky looky, it's Anguirus! Or Angilas, or Angweenus, forget it, he has too many names. Anyway, this solves the mystery of Anguirus, the scrapped character. Production on him stopped before they created(or maybe before they programmed) any attack frames, so all you can do is walk, walk, and walk. But, pressing the turbo button will activate his "destructive walk", which is overpowered, as you can see. He also floats during Monster fights which prevents him from killing Mogera, Varan, and any other short kaiju, which is most I believe. He loves to crash the game on the base levels, which is annoying.
Now about Rodan, here are his sprites: http://i.imgur.com/m6Ffn6N.png How he would have played like will probably remain a mystery forever, because loading his character file automatically skips the level, but his name can be seen above the health bar. Attempting to fight a monster crashes the game, so I can safely say Rodan can not be played as at this time. He'd probably be similar to Mothra though.
This scrapped character actually does load in the American version but the new title screen messes up the placement of his sprite tiles and loads parts of the Title Screen instead. You still get the character, but not his sprites. However, if you paste Anguirus' tiles on top of the Title Screen sprites he will work. This is actually better due to the fact that the US version does not crash while playing as Anguirus. This cheat does work on the Wii FCEUX emulator.
And finally(ugh, this is a long description), for those curious, loading an enemy's character files will crash the game, but you'll see their name above their health bar before the game crashes.
And now for an edit, this is indeed real, input the code 0127-01-03(I happened to memorize it) while playing on the Vituanes or nnnesterj emulator(or really any emulator as I found out). If you don't want to believe it, too bad for you. I understand what you're thinking "This is a mod!" But hey, remember when many of you doubted Biollante and she turned out to be real? Well, same thing here. He's real, whether you like it or not.