Google has tweaked heads-up notifications in Android P developer preview 2, though not by a huge margin, rather just slightly by adjusting the animations and making them a little bit more lively and visually noticeable. If you've already flashed the second developer preview for Google's upcoming version of Android and you've already gotten an incoming notification while the display was on and you were using the device, then you'd have likely noticed how the animation has changed, coming with more of a bounce than then it currently does in Oreo and prior.
Not only does the animation have more of a bounce to it but the animation is fairly smooth too, launching outward from the status bar icon for that notification and finally expanding to a screen-wide panel, though not all the way as there is still room between the sides, top and bottom of the notification and edges of the display so you can see the underlying home screen wallpaper and any widgets you may have on-screen. Google has also made it so that heads-up notifications disappear off-screen in near the same way as they appear, fading back into the status bar icon where it came from, though it is worth noting that this only seems to happen if you let it time out.
Current heads-up notifications will simply drop down from the top of the screen, and when they time out they disappear back into it, unless you swipe them away of course. This new shift towards making them a little more animated is likely to go over well with users who have appreciated all the focus Google has put into bringing system animations to the platform. Google released the second developer preview for Android P on Tuesday, May 8 at I/O 2018, and has made it available to flash as a system image for those with compatible devices. It's also going to be coming to a number of devices over-the-air as part of Google's partner program for the Android P beta.