If you ever get hurt in this D-Mod, go the south-east part of the island and you can get some hearts.
Go the the house left of where you started (you don't have to kill the pill-bugs, but it's a bit easier if you do :) and go upstairs. Talk to that over-sized woman and you'll learn that her son is missing. Go outside again and go to David (west). Talk to him, and he'll ask you to hit him, so do so. Talk to him again and you'll learn that he hates Papa Georgio. Tell him that you'll beat G. up, and go to the Pizza Parlor. Just hit him once (he's invincible anyway) and tell David that you beat the hell out of him. He'll give you his amulet, equip it and go back to David's mom (the big woman) talk to her again and she'll rush over to David. Back to David once again and he tells you that everything is ok with his mom now. Now go back to the screen where you started and check the fountain... The End?
Just one of them. If you didn't kill the duck on that screen he'll give you a hint about a deadhead. He's talking about the skulls in Papa Georgio's Pizza Parlor then. Load a saved game, or start over and go the Pizza Parlor, hit the left skull 3 times and talk to it. He'll give you a clue about the secret area. Get the medal again, just like you did before, and go to the screen north-east of where you started and use it (attack button). A rock will disappear and you can pass. Just talk to the knight standing there and if you finish the game now, you'll get a different ending message.
There is another different ending if you kill the duck before checking the fountain.