Metal Jack came out in Japan, but the game went unreleased in North America. About a year and a half ago, a collector bought a prototype of the unreleased localization from DreamTR and released the ROM image of it. This release kind of few under the radar for me, and it wasn't highly publicized until now. I managed to find quite a bit of magazine coverage of the game. Considering how bad the game is, I am not altogether surprised that it did not come out. I made an article on this game for my website.
http://www.snescentral.com/review.ph...&article=proto