I am also not sure if I am completely right, but I´ve written the code for two iPhone games with ShiVa and tried to write some basic player movement a few days ago. And what I wrote are some of the things I encountered while doing so. It was an interesting experience, but I never enjoyed the coding and am happy that there is Unity as a more expensive but definatly a lot nicer alternative.
But I am still a lot faster to get things going with gamestudio than with Unity.
I am probably just too stupid to find nice and clean ways to do things, but well, what I wrote is what I experienced.