If you want to make a fan game, make spiritual sequel instead.
Nintendo can’t do much about games that are very similar to Mario, Zelda or Pokemon for as long as they do not copy any assets, (some) names or levels from those games. Based on the videos the main character is unique but most if not all the other art assets are direct copies from the original game.
Lemmy support would be much more fitting for Mozilla. They could add plugin or lemmy integration to their browser that could show discussions from subscribed communities matching the current url.
Effectively acting as a “comment section” but for any page. One would only need lemmy account to comment on youtube videos, news articles, blogs etc.