Let me be as clear as I can be: the iOS multitasking bar does not contain “a list of all running apps”. It contains “a list of recently used apps”. The user never has to manage background tasks on iOS.
Nice well documented article debunking some common misconceptions about the multitasking on iOS devices. Still doesn’t explain why some large games quit or don’t even start on my iPad, to which the only working solution I found is to close all the apps in the multitasking bar and then restart the device.