In Europe, the word “ninja” was considered to be too violent, thus the name of the game was changed to Teenage Mutant Hero Turtles. This would also include any other products from the franchise.
The box art from the game shows all 4 turtles wearing red masks on their faces. This was taken from the comic books where they did not have colors to distinguish them because the comics were printed in black and white.
Oddly enough the NES/Famicom version of the game was the first TMNT product to be released in Japan. It was called Legend of the Radical Ninja Turtles.
TMNT was the 7th bestselling game on the NES with over 4 million copies sold. This may be because of the popularity of the series though, as it was received poorly due to its difficulty.