I run a small Android game design company, and I have experience in writing programs for different types of games. As well, I also have a lot of experience with drawing in Photoshop, both realist renders and animated designs.
If necessary, I also employ an animator/artist who can work full time to make sure the project can be done in a timely manner.
I can provide a mock-up/sample prototype of the working game within a week if the concept is simple enough.
And lastly, the engine I would use to write the game can compile both to Android and iOS if desired.(however, I do not have an iOS developers account)
Extra time to complete this project would only be necessary if the concept is difficult to program.