if your familiar with the Sega Master System, you'll remeber a game called Wonder Boy that was an exact copy of Adventure Isnad for the NES, The main character was changed but you can obviously see it was the same game....and it wasn't even once, everytime an Adventure Island game would come out it was mirrored onto a Sega Master System Game as Wonder Boy 2...3...4...whatever, and Hudson does not have its name on Wonder Boy so what's up with that?????
Compare Screen Shots.....
http://www.defunctgames.com/lookalike028.htm