The title is a reference to the fact that this was the first Konami game to be released on CD-ROM.
The robot Metal Gear was designed after the bipedal tank from the game Metal Gear (1987). But unlike that Metal Gear, this one doesn't carry any weapons and is around the size of a small animal. The introduction scene pokes fun at this by making the shadow of Metal Gear larger than the robot itself.
ID files for Hideo Kojima and other members of the game's development staff can be found by typing their names into Gaudy (JORDAN in the English version), the computer that's located in Junker HQ. Some of the profiles and staff members may vary between versions.
The Sega CD version has become a popular collector's item and is also by far the most expensive one, having a price-tag of several hundred dollars on eBay. This is mostly contributed to the fact that only a few thousands of copies have been sold. Additionally, the Sega CD version is the only version of the game that has been translated into the English language.