When ports are discussed people always seem to compare raw specs but never consider the subtleties of actually porting games, I think we discussed that on the magician lord mega drive tech demo thread. SignOfZeta is right.
Just the quality of the porting makes a huge difference. Look at the 16-bit Street Fighter II home ports that Capcom handled in-house vs the ports that SNK games got at the time.
I recently got Mega Bomber Man on Genesis, and although Westone handled the port, you can tell it didn't have the care needed to bring it on par with the PC Engine original. The foreground effects are gone, the color is bad, slowdown is everywhere, the music is a downgrade. Lords of Thunder on Sega CD is missing effects.
Contrast those ports with Snatcher for Sega CD. One of the contributions I made to the recent video on our Youtube channel was just how well Konami handled the Sega CD port. They used programming tricks to achieve nearly the color fidelity of the PC Engine, and nearly all the effects are intact. It has one of the best versions of the soundtrack. I think that specific point must not have made the final video, but anyway, it's an example of a port done right.
