Pachinko Kuunyan

Pachinko Kuunyan is the only pachinko game on the Mega Drive, including the Mega CD and 32X.

They compensated by making it somewhat bizarre and giving it an adventure game-like overworld.

Dummied-Out Cheat Code?
Hold Up + Right + A + C + Start on boot. If done correctly, a sound effect should play during the Sega logo. Unfortunately, this appears to be the only effect of the cheat code; if anything else was there, it may still be hidden. Alternately, it could be the only remnant.

I.S.C. Logo
After beating the game, press Up + Left + A + C + Start during the credits to display the I.S.C. logo. For the record, they're still in business and primarily specialize in pachinko games for home computers, appropriately enough.