Conquer the galaxy - Game App

We are interested to produce a game app in Unity3D. Why Unity3D? As I understand with this game engine I can use it for all Mobile phones (iOS, Android and Windows Phone 8, maybe also facebook (<- this I'm not sure)). There should be a free trial version and the buy version. Enclosed I wrote a game description. Similar games already exists and the game play is nothing new. An example is in the description, please play the game and you understand what I want. (just 3 parts are different from the example: 2 ships instead of 1, a small research part and a different menu design) The tricky part is the level design. I don't want to contact the programmer each time, to change a small detail, so I need something very simple which makes the level design very easy. (also an example is in the description). To be honest: I'm not sure if the project will be realized or not. Because this is nothing new I can't charge a lot (something between free with app-in for bonus points or 0.99 $), for that reason I can't offer an high budget. Beside that I have 2 other projects on the run at the same time. So if the price is okay and it’s not so time consuming, the app will be realized.