sources? i've never heard ANYTHING about MGS2 or 1 being a parody. it is a serious game man!
Edge magazine. They do an article/interview on the metal gear series like every few months.
next-gen also go on about MGS regularly (I think the last BIG ONE was in early jan/December)
Also on a side note, do you really think they are serious games? A game where a boss can tell you've played castlevania, where there is CYBORG NINJAS and WALKING NUCLEAR MISSILE TANKS and where the plot twist at the end is "YES, MR PRESIDENT". Everything about MGS is so blatantly over the top to the point where it's effectively wearing a T-shirt saying "HEY THIS IS A JOKE" and it's wagging it's dick in your face.
The bosses were a very big part in the whole "Video games are gay" point. So let's just focus mainly on that for the time, how videogames would have cliche bosses who get progressively sillier as you go on is something Kojima frequently mentioned in the 90s about how games can't be realistic... So MGS had a slinging cowboy/sherrif (Ocelot) a psychic who could be defeated with a forth wall concept such as using controller two (Psycho mantis), a cliche bond/cold war sniper babe (Sniper wolf, with enough cleavage for two), a fucking CYBORG NINJA (Cyborg Ninja), Heavy Weapons guy, with totally inhuman strength (Vulcan Raven) and a fucking walking tank with a
RAILGUN THAT FIRES NUCLEAR WARHEADS. That is of course leaving out the old action movie staples such as rooftop helicopter and jeep chase, but they seem more dud to me.
(It's all very ironic as the MGS series have proven themselves capable of being called art (Note: I don't even like the games personally, so this is hardely fanboy rant) yet Kojima constantly is an ass and makes the claims that videogames are a form that cannot be art)