Start point: one full size image (iphone or iphone size) with balloons, ex 500 balloons.
user clicks on one balloon,and balloon explode (with explode effect) (and triggers function call to decrement ballon count).
game stops when count = 0.
8 freelancers are bidding on average $178 for this job
No problem, I can do this with Unity3D ands give you an awesome app fairly quickly. Check out my profile at [url removed, login to view] and see what I do.