mario bros' gravity

Hello! I have decided to work on a fan-game called "Mario Bros' Gravity." You can walk upside down, on the sides of walls, or anything. You have to get Mario and Luigi to the end of each level, exploring places upside down, or basically anyway that defies physics or gravity. In each world, starting in space, you must find and defeat each Koopatist. (Scientist.)

Okay, here's the synopsis.

Bowser has kidnapped not only Peach, but all of Mushroom Kingdom and shot you into space via bullet bill. Bowser hires Koopatists to alter gravity and to through you off your way. Defeat them and save the whole universe!