If you've already played the one hole from 3D Ultra Mini Golf, you'll want to get this plug-in for the demo that adds another hole. This is The Incredible Machine Hole. You'll need to extract the new holes into the /DATA folder of the Minigolf directory.
||Free to try
||486DX2/66, Windows 95, 8MB RAM, 31MB disk space, DirectX driver, 3D Ultra Mini Golf demo, 256 colors, Sound Blaster 16 or compatible sound card