Obtrusive notifications If I'm playing a game or watching something in full screen, why does the notifications come over it? I've noticed especially whatsapp notifications fill up the screen.

I need to be able to only stop the heads up notifications when in game mode or full screen watching video, not totally turn it off. is there a way to do that?
Answer to first question: Because Google wanted a new notification system that was more visible and obvious, much the way iOS handles their notifications. A lot of defectors from iOS actually missed that.

Answer to second question: this is done on a per-app basis, for those that support it. Most apps don't even use the feature, but for those that do, some allow you to disable the pop-ups, or heads up notifications. But that's the only real way to do so without potentially disabling notifications in general.