if you can become root (if you could chmod the directory then I supose you can) then login as root and delete the folder then.
the easiest way is to delete the directory from some file manager (konqueror in KDE or somethin' else on some other desktop env.) - you can delete it recursively then. Of course the file manager must be run as root.
or in console use the midnight commander.
But the most secure way is to uninstall the game (but don't know how to do this

)