Write an iPhone application

2D game. Different objects appear on the screen. The player then selects and throws with a sliding motion the objects (ex: balls) into the goals, which will score points. The game would have several levels of difficulty or challenges. For example, a bomb instead of a ball appearing. Need to optimize graphical objects as well to avoid any lagging or whatsoever during gameplay. Tell me that if you are capable of handling the graphical design part. The App is offline - should have a free demo version and a full version. To make it interesting, the game can be played by four players. The app needs to be approved by the App Store and to work fine on iPhone/iPad. Looking for an efficient designer for this and future projects.