Considering that Nintendo showed the game off to press exactly once back in 2014 and it hasn't been seen since, this probably shouldn't come a much of a surprise. When we got a chance to check it out, Anthony Agnello said that it felt incredibly shallow and would seem out of place even in mini-game collections like Nintendo Land and Wii Play.
"Even if it were just a mini-game attached to a larger collection, Miyamoto's Project Giant Robot experiment would feel thin. Funny, as quickly silly as a round of Duck Hunt, but thin."
Maybe this isn't too tragic a loss then.