I am a full time game designer, developer and reskinner.
I've been a software developer for 25+ years. My current expertise is Unity3D and specifically iOS and android games. But in addtition, I am very experienced with Objective C for iOS, working with Cocos2d and Spritekit.
I have a team of artists who handle that side of things, as in my experience its rare for a developer to be good as an artist and vica versa.