Going into the 27th year of playing Metal Gear games, some of you have asked yourself at one point or another why Hideo Kojima chose the name Solid Snake as the name for the main character. Kojima took to answering some of those questions on Twitter recently, and should give you some light on the reasoning behind it.
"The reason I used Snake as code name in MG was Snake was the most appropriate symbol of living thing that hides his presence and sneaks without any noise."
"The reason I didn't make any specific snake like cobra, anaconda, viper was because the protagonist is the player. The reason I use Solid was to give opposite impression of soft image."
So what about other names in other Metal Gear games, like the original, and others like Snake Eater and Sons of Liberty? Nake Snake and Solidus Snake were explained as well.
"Like of all endings of any series are, the appearance of strongest enemy was a must in MGS. It's Snake who can surpass the Snake. Thus I brought about 'clone'. Solid vs Liquid. That is MGS."
"As to develop sequel, the 3rd snake was needed," he said. "Since both Solid & Liquid express state, means same true state. Naturally the next would be gas, but gas snake is like gas human, not handsome name."
"So I borrowed from physics terms of "solidus/liquidus". Solidus is not state but implies the boundary of liquid and solid."
I hope that helps shed some light and explains things a bit for you. Personally I've always wondered what the names represented as well. It kind of takes you back to a day when there were a lot less polygons and complex hardware moving at lightning speed.