One character sees a makeover due to copyright issues.
The Virtual Console release of The Revenge of Shinobi for the Sega Genesis (Megadrive in Europe) has seen an alteration due to copyright issues. The character of Spider-Man (who makes a cameo appearance as a boss) is now pink, so as not to fully resemble the original Marvel Comics character.
This isn't the first time Sega has faced similar issues due to special characters appearing in the game. Three versions have been released, each featuring variations of boss characters. The first version of the title featured bosses resembling Batman, The Terminator, and Godzilla, as well as an officially-licensed Spider-Man. In the third and final version, Godzilla was altered, but Spider-Man remained.