While screen brightness could not be changed for the better, you might want to look at an updated test with the battery....
http://www.anandtech.com/show/8329/revisiting-shield-tablet-gaming-ux-and-battery-life
Almost 4 and a half hours of T-Rex demo is nothing to laugh about when you change the battery setting to cap the demo at 30 fps. Also remember that compared to the shield portable, the shield tablet is running at two resolutions higher with a far larger screen.
That's an hour longer then the tab s from Sammy, and with far better performance then the rest of the samples.
I'm In no way saying this tablet has a perfect battery life. But for most games and typical uses, you can even change the battery setting to have more aggressive savings while still running games or other tasks. All with little or no real loss of quality or lagging.
Posted via Android Central App using the all new HTC One (m8)