The early and late versions of The Super Shinobi for the Mega Drive.

The Super Shinobi, Released on December 2, 1989 and re-released in late 1990.
It is well-known that there are two versions of this game in Japan. 
The existence of the resale version was made known to the public by the 1991 publication of "Mega Drive FAN" (Tokuma Shoten) , and it was subsequently featured in numerous commercial magazines, so it is likely that users at the time were fairly aware of its existence.
They are  the so-called " Godzilla version" and the " Seaboz version"
In the early version, the monster that appears in the stage resembles Godzilla
In the later version , it is a monster made of bones (like the Seaboz from Ultraman ). It also seems that enemies that resemble Batman and Rambo were changed to different characters in The later version of Super Shinobi. Spider-Man was not removed, but copyright information appeared on the first screens of the game however due to license expiration, Sega decide to change it to a "pink" enemy in the later releases of the game.
 
 
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How understand wich version is without playing the game?
You can find it out looking at the box, manual and cartridge.
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1- The early version has the announcement page for Yuzo Koshiro's CD removed from the instruction manual.
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-2 The SEGA logo behing the cartridge

Early version → There is a circle c mark behind the logo

Late version → No mark
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3- Bottom left of the back of the package
Early version → MADE IN JAPAN notation
Late version → No notation
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