Solids description is actually a better description of Metal Gear then Metal Gear Solid(but MGS cribs from the previous games so much it's not really much of a hit). That and the fact a major plot of Solid is the US government doing stuff that it really shouldn't have been and Snake was part of a cover up without realizing it.Johnny Novgorod said:Metal Gear Solid
You play as Snake on a mission to save someone and/or sabotage something. Your boss was the bad guy all along.
Metal Gear Solid 3
It's a prequel starring the will-be bad guy from the first (two?) games. You kill the original Big Boss. Everybody likes this one.
Minor Quibble with 3. You don't kill Big Boss, you kill The Boss, who was Big Bosses Mentor/Mommy figure. But she plays kind of the same role that Big Boss does to Snake anyway.