Game & Watch was released in November as part of Nintendo's anniversary edition and features both the original game NES as well as its Japanese sequel, known in the West as Super Mario Bros: The Lost Levels.
In fact, he had posted videos on his channel that showed how he achieved it, but as he revealed via Twitter, two of his videos have faced copyright claims and are no longer available for viewing.
The system Content ID of YouTube, designed to identify copyrighted material is usually automatic. However Stacksmashing scored on another tweet, that these videos were manually targeted by a Nintendo representative.
As he told Gizmodo, one of the downloaded videos only includes footage of Super Mario Bros. embedded in device. There are such shots in many other Game & Watch videos.
The other videos included material from the NES version of The Legend of Zelda.
Three videos with a violated Game & Watch currently remain on its channel. It is not clear why these have not been highlighted.
Gizmodo notes that copyright claims specifically address their use video, which you can find in other videos, and not in the instructions he gives on how to hack Game & Watch.
Stacksmashing claims that Nintendo did not contact him about his YouTube videos or the pirate content he shared through Twitter before removal. YouTuber has edited both videos and is now reporting in the hope that YouTube will bring them back.