Yeah, you just have to know how to alter the path correctly which can be a little tricky. Can I make a suggestion? Copy all the files in that folder you provided the screenshot of, right? Now go to your WD at the top level and make a new folder named Test. Paste all those files in there. So now alter the script to say this:
forfiles /p G:\test /s /m *@.* /c "cmd /c del /q @path"
It's just a lot easier to test if the folder you're using to test is one single word right on the root of the drive.