The Genesis, curiously, didn't have nearly as many small-print-run games as other systems. Generally, the quirkier Japanese cult classics that would see small US print runs, like period strategy games, weren't released at all for the Genesis, as the system wasn't nearly as successful in Japan. That said, there are a handful of rarities. Thus, originally very loosely based on a similar list in Tips and Tricks magazine, along with help from the Retrogaming Roundtable (www.digitpress.com/forum) and a pile of old copies of GamePro (a youthful indiscretion) for game info, I give you an As-Comprehensive-As-Possible list of rare, non-prototype Genesis games. (All of these refer to the American NTSC versions. A PAL rare list would be much longer, as many games were released in limited quantities in Europe.)
(The format is "Name - Publisher - Reason for rarity/interesting facts)