Instead of shipping copies to stores Nintendo made a handful of gold Punch-Out!! cartridges which were given out as gifts for a Famicom golf tournament. That sparked demand and eventually led to a retail release.
While waxing about the series In the latest Iwata Asks column Wada, one of the designers of Punch-Out!! for the NES, explains he drew Mario as a referee without permission.
Wada also shares a neat secret about Punch-Out!! that hasn’t been documented before.
“This is a great opportunity, so I have something I’d like to say. In Punch-Out!!, the game gives you a lot of hints about effective timing of punches. There is a big boxer called Bald Bull in the NES version as well and a light flashes to the right in the audience when he charges. If you punch when it flashes you will land a body blow.”