Wing Commander CIC

Hey guys, question: What's the differences between the original PC versions of the Wing Commander games, and their various Super Nintendo/Sega CD/3DO/Playstation/Game Boy Advance ports (assuming there are any and they're not all just straight ports)? I've heard that in some of them, missions have been changed and replaced etc, and not long ago me and another member here discussed the SNES version of Wing Commander 1.

Thanks in advance.