I can Deliver Flappy Bird App in 3 Days. We are a team of 2 iOS Developers, and 2 in-house designers with 7 years of experience. They can design you a high end custom theme and art-work. Also we can make adjustments to the original version of the game to make it easy or harder.
I am available on Skype 16 hours a day so communication won't be a problem. Drop me a message if you have any questions.
Regards,
CX