I've been wracking my brain to try and figure out why you'd want to do this, and I can't really come up with anything... but I'm going to show it to you anyway because, hey, I have space to fill here.
So if you pop in your Super Bomberman cartridge and go to the Password Screen, you can put in the password "5656"
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Which will take you back to the title screen (a little anticlimactic), but then!
Start a game to find
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That Bomberman has been shrunk down to pint-size!
I haven't actually figured out how this is useful yet. But once I do, I'll let you know.