Assuming this hasn't been fixed by now, apparently the Steam Sega and Master System collection has a version of Revenge of Shinobi that retains Spider-Man and Godzilla's original designs, before the copyright ninja's forced revisions. You can supposedly access this through the "Simple launcher", which is a simplified emulator for compatibility purposes. As opposed to the primary launcher, which takes you to a rendered bedroom, and a more "advanced" emulator.
The primary emulator can only access an up to date version of ROS, where Spidey is decked out in purple and black colors, and Godzilla is reskinned to look like a skeleton dinosaur.
Examples here:
YouTube video
You can see why revisions had to be made.
I suspect this was some clever devs way of slipping it under the radar. Inspectors will probably check the main product, and not the "compatibility" simple launcher, as the menu is a ***** to navigate and the roms are out of alphabetical order, and contain duplicates.
The point is, if you have any interest in playing a legend in copyright infringement, it's selling for 10 dollars. Well worth it, imo.