Predicting a legal takedown notice from Nintendo's Lawyers in 3... 2... 1...
Nintendo is extremely strict about protecting their IP. Mario by himself is worth roughly a bajillion Yen as the #1 most recognizable game character, and Yoshi is close behind as the #3 most recognizable game character.
Their legal department is aggressive both to take down sites and take other legal action against infringers.
Is this guy serious? Buddy, take your legal preaching to the thousands of other Mario fan games that both have more "recognition" than this fan game and are more infringing.