New 4.4 Kit Kat feature: access status bar and notifications from all full-screen apps
I thought this was a really cool feature worth mentioning (and I hadn't seen it in reviews so far): in 4.4 Kit Kat you can access the status bar and notifications from full-screen apps with a swipe down gesture. This is not just from new apps written with the "full-bleed" UI introduced in Kit Kat, but from existing full-screen apps as well, like games.
I really want to use this for myself. It seems like when I'm in the camera app I often need to check notifications, the time or battery life. With Kit Kat I won't have to exit the camera app to do so.
Always-Accessible Notifications In KitKat (via Android Police)