I'm working on a game that I'd like to ultimately be available for Mac OS X and iOS. What's the best way to do this? Should I (1) focus on one OS first and get a polished version 1.0, then port to the other OS, or (2) should I try to develop for both simultaneously from the start?
If (1), which OS should I target first, i.e. which porting direction is the easiest?
If (2), do I need a separate project in XCode for each OS? If so, how do I maintain just one copy of the platform agnostic code that I share between both projects?