My answer is obvious with Zone of the Enders 2ND Runner but very close to that is Snatcher IMO tho IMO I think both are better than MG but that's just me.
BTW this is released games not demo's of unrelased games.
If none of the poll options suit you here is his wiki. https://en.wikipedia.org/wiki/Hideo_Kojima
He also worked on Beatmania,Boktai series,Penguin Adventure,Lunar Knights and more.