here's an idea of how we could implement the gravity-changing:
http://www7.picfront.org/token/y4KU/2010/02/03/1753351.jpgarrow keys for movement, WASD for gravity direction:
1: jump (space key)
2: while in the air there's a slow motion effect. not overdone, but just a tiny little slowmo. press W (only works in the air, no gravity-changing while standing) to change gravity direction. Player turns in the air quickly (slow mo is over) and lands on the top side, because gravity pulled him there.
3: moving with the arrow keys
4: jump (space)
5: player presses D while in the air -> gravity direction change. player is pulled into the pressed direction and lands.
6: player can move on the new surface.
