Abrader, that's kinda distinguished mentally-challenged. 
MGS4 is pretty awesome. Finish it first before replaying games you've already beaten.
yeah - but plenty of time and that mg-msx song in mgs4 stimulated much fan-service-nostalgia-gasms...
On this topic of classic MG -
While I have finished MG NES and MG MSX, I have only finished Snakes Revenge NES (which i liked) but not the true zanzibar mission in MG2: Solid snake MSX. I really want to play thru that some day - it seems excellent and its from a Konami era that I absolutely love.......
While MG2 seems better than snakes revenge - I in some ways (not the audio

) prefer MG NES to MG MSX...I think parachuting into the jungle and using the truck to infiltrate the outer heaven main gate at the beginning of intrude N313 is much more epic than swimming right up to the back door (ala the shadow moses incident) in MG MSX. MSX MG still wins on top for a few reasons (such as the music

)