This is just a little idea I had for a platform puzzle game where you reverse gravity to reach the goal in the level. I used Construct's physics engine to make this.
http://machriderx.googlepages.com/gravity.zip
This is just a demo of sorts. Just a way to test the game idea I had. It kinda sounded better in concept than it did in actuality. I'm not sure if it would make that great of a game but then again I don't know. I like how easy it is to experiment with different ideas in Construct though and to see what works and what doesn't.