Here is my works that I've done in Global Game Jam, currently 2011 is my first Global Game Jam that I've attended where we were to create a game within the span of 3 days (48 hrs approx)
Global Game Jam 2011
Grab-vity was essentially created for the theme of GGJ 2011 "Extinction". In a nutshell we brainstormed several ideas and selected one, in which was the extinction of life, not on our planet but on unknown planets beyond our solar system. Outside our solar system, as represented within the game has a massive blackhole with a SUPER strong gravitational field that is sucking all the planets into its gaping maw, it is so strong that even the stars and meteors are being sucked in as well.
The gameplay generally revolves around a drag and pull system where you as a player use your "hand" cursor to drag and toss away each planet that is consistently being sucked towards the black hole, these planets replicate the realism of being a large mass as such that when a planet collides with another a large explosion destroys both planets.
Within regular intervals the game spawns meteors that are indicated by red tracer fireballs that can collide with the planets, not to destroy them but "bump" them abit and knocking them abit off their course towards the black hole.
There is essentially no room boundary within the game as each planet can be tossed out of screen and eventually come back in screen and move back towards the black hole. However this is a risk as you cannot prevent two planets from colliding off screen in that event.
What really made our game what it is, is the fact that we added a gravitational force within the game itself to act as a realism factor, the planets dont stop and turn 180 degrees and move towards the black hole, they slow down and make a curve turn, as with how you throw a ball into the air and it falls (example).