I whipped up that list quite quickly, so it's quite possible I made some errors and I didn't have time to look into some details.
-Like how/if the Genesis and Sega CD versions of the two Ecco The Dolphin games are different.
-Or how the bonus games are enhanced, and if the Space Harrier II maps we have count, or if the enhanced version needs its own maps.
-It looks like Rainbow Islands Extra is a Japanese Mega Drive game. Haven't checked to see which other games, if any, are not originally North American releases.
-Not sure if the green "O"s (to mark completed map sets) are all correct. Also have some blue "?"s for some that I am not sure if they are actually complete.
If any Genesis fans see any errors to be corrected or things to be tweaked in the listing, definitely feel free to let me know.