Power8 is one of the many Start Menu replacements apps aimed at Windows 8 users and even though no updates have been released lately, it also works okay on Windows 8.1 Preview too.
As you can see in these screenshots, Power8 isn’t quite a Start button per se, but only a small icon on the Taskbar that allows users to launch a Start Menu.
It doesn’t replace the built-in Windows 8.1 Start button, so it could be quite difficult to click on it. At the same time, it seems to mess up the other Taskbar button, but the original look is restored once you close the app.
Of course, these are most likely compatibility issues that could be easily fixed with a software update, so keep an eye on our Windows software section to find out when a new version becomes available.