Rewarded at the end of each phase, Drebin points will allow you to unlock new Metal Gear Solid inspired iPhone wallpapers. Kojima Productions will seemingly be getting the game out a bit quicker by splitting it in two; a version with twelve stages will released in the spring, with an update coming later that will add the remaining eight stages at no extra cost. For those who've already bought it, at least.
Check out the official website for an illustrated look at how the game will play.
[Via Pocket Gamer]