if you only want to touch one game in the metal gear franchise, make it mgs3. it may not be my favorite of the series, but it is the game that perfects metal gear. gameplay, story and kojipro's love for movies hit a operatic and harmonic crescendo in mgs3 that i've struggled to see replicated in any game since, though many have certainly tried. cinematic gaming is it's own sort of genre for better or worse, and the bones of mgs3 can be seen in every entry in it since. it's a unique experience that deserves it's position in gaming history as a benchmark.

also naked snake can find and eat tsuchinoko, a legendary yokai in japanese folklore in the form of a snake, which slaps i think