What we do know so far is that it's not a Nintendo game, it's not from Japan, it's over 10 years old, it's not an arcade game, it's not for any of the machines currently supported by the Virtual Console and it's 'never been seen before'. Interesting stuff!
What could this mystery game be? We will keep you posted! In the meantime keep your eye on the Rllmuk thread for up to date news!