About the gravity and jumping discussion; the gravity is the same in The Mushroom Kingdom and in the real world. Humans don't have special jumping abilities(Peach floating, Mario and Luigi jumping high, Yoshi's flutterjump), my guess is that they're born like that. Toad jumping as high as Mario or Luigi is just a cartoon expression showing that he's shocked. Also the Paper World and the real Mario World aren't two different worlds. Think: The Mushroom Kingdom, Shine Sprites, Peach's Castle, Bowser's Castle, etc. These all fit perfectly into the real Mario World. This was already mentioned, but some things in the Paper World were put into future Mario games(Tutankoopa, Star Spirits, etc.).