Improve Unity iOS 2D game + export to Android and Flash

I need to improve already existing Unity iOS 2D game ( Moverama on Appstore, there is iPhone and iPad version ) and export it to Android and Flash. There is need to be replaced Openfeint by Gree, remove bonus menu and replace it by in game bonus buttons, add tilt control and make few other slight changes. Mainly the game is missing addictive game play so players can play it much longer and will be motivated to buy in app purchases much more. There is need to make a web application for sending cash prizes to players with highest score directly to their bank account through Apple ID, without need to ask them to provide their bank details and by different way to other platforms. Gree has to have one united multiplatform score table. There is need to make some graphics, mainly in game buttons and so on and it has to be not recognizable from original graphics, but if you don't make a graphics, we can provide it. Have you a creative ideas? Do you know improve the game enough with least changes?