This the first tool for Windows 8 posted on TheCustomizeWindows. Simply use the provided batch file to have the Windows 8 M3 like Windows Task Manager in M1. Developed by andreascy.
This is the Modern Windows Task manager of Windows 8 M3 leaked screenshot:

Alternate way to get Windows 8 M3 Windows Task Manager in M1
Go to the following key in Registry Editor :
HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionTaskUI
In right-side pane, create a new DWORD value TaskUIEnabled and set its value to 1
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It is tested on Windows 8 7850 build by the developer.
It is nice to have first free Tool.