There is a thing called fair use. The footage can be used for a review, but any footage used outside of a review would be an infringement.
I can understand them objecting with someone showing the whole game, where a person could not see a need to purchase it, but having a small snippet of footage with your character being worthy of a strike is just them being an ass.
That’s one of many reasons why I’m not a big supporter of Nintendo. They barely got money from me for 3DS games, and hardly any more for my used (boxed) Wii U, when it came to purchasing games.

