Put in changes to make Sea Assault and Ant Planet work better with multitasking. So, the games should pause in the background properly. If OpenGL is used in the background, then the game content might have to be reloaded into the context when you bring the app to the foreground -- the OS will terminate the app if it finds out your using OpenGL. Since I enabled multisampling, the programs are linked against the iOS 4 sdk. Just pause in the background. Same code for handling incoming calls too while playing.
The second generation iPod and the 3G phone do not have multitasking in iOS 4. On that hardware its like the old iOS 3 behavior.
Submitted the fixes to iTunes Connect.
Also, I notice if you have developer logging turned on, the logging can cause animation hiccups while playing. I figure most people will not have that enabled.
Sort of a pain to debug the iPod with iOS 4.0. For some reason, if you type in your wireless network password it will not accept the shift key! All lower case! But looks like iOS 4.01 handles this properly. iTunes currently does not update iOS to 4.01 for iPods -- think the main purpose of this was to fix the phone reliability issues. The only way around it was to use the iPhone Configuration Utility with network settings.