Gravity Sling is one of the first iPhone games to take advantage of Apple's new policy allowing In App Purchase from free applications. What does this mean: You simply download the free game and enjoy the first 15 levels for free. If you like it, you can purchase the next 30 levels. We must admit that we haven't played through the first 15 levels yet, so we can not give you the price for the 30 following levels. Our guess is that the price must be somewhere between 0,79€ et 0,99€.

So what is Gravity Sling about: Gravity Sling is puzzle game where the player has to use the gravity of nearby planets to sling the little astronaut through space trying to safely get back to the space shuttle.

"We are extremely excited to be one of the first to take advantage of In App Purchase from free applications," said Brian Robbins, Founder of Riptide Games. "We believe this gives players a much better and more seamless game experience, while allowing us to provide the best game we can to the player."

Gravity Sling also connects the popular OpenFeint platform enabling integrated leaderboards and achievements throughout the game. It is the result of a collaboration between Riptide Games, PyroMonkey Productions, Spatial Reasoning, Crucial Games and NoiseBuffet which are all Denver-based iPhone developers.

And a small video of the game: