Allowing applications to play nice(r) with each other: Handling remote control buttons
If your media playback application creates a media playback service, just like Music, that responds to the media button events, how will the user know where those events are going to? Music, or your new application?
Making Android Games that Play Nice
Making a game on Android is easy. Making a great game for a mobile, multitasking, often multi-core, multi-purpose system like Android is trickier. Even the best developers frequently make mistakes in the way they interact with the Android system and with other applications
More Android Games that Play Nice
Android users get used to using the back key. We expect the volume keys to work in some intuitive fashion. We expect that the home key behaves in a manner consistent with the Android navigation paradigm.