First off, I'd crack that sucker open with YY-CHR or what ever you use for editing graphics. Take a cursory look to see if there are any extra graphic present.
If so, you have a good lead. Next you want to determine the value associated with any existing power ups. Then tweak those to see if anything unexpected happens.
Thank you! I eventually found the items, but there weren't any extra ones like in the other games. However, I did find an enemy that I had never seen show up in my normal playing, so I want to see if I can get it to appear. I've never done anything like this before; what do you mean by "value" and how do I determine it?