You already saw a few things the overview button can do in our split-screen video demo, but that's just the tip of the iceberg. Google is taking app switching seriously in Android N by turbocharging the overview button. You can now switch between open apps without touching anything but that one button. Check out the video below for a demo.

You can now flip between your current and previous app simply by double-tapping the overview button. That's something that other ROMs have had for a while, but there's much more here. If you just keep tapping the button you'll cycle through all the open apps. At the top of each card is a countdown progress bar that will automatically maximize the current app in about a second unless you keep hitting the button. If I'd seen the video above yesterday, I would have thought I was looking at a custom ROM or wacky Xposed module. The overview button is suddenly very powerful.

As previously mentioned in our split-screen post, a long-press of the overview button opens the current app in split-screen. You can use the same double-tap and continuous taps to switch between apps in split-screen mode too. The only thing it doesn't appear to do right now is the countdown progress bar—you have to tap a card after shuffling through your open apps.

It does seem to work pretty well for a dev preview. Most of the lag you see in the video is due to screen recording.