Well...
All I can say is that people have strange tastes. I've been baffled by Newgrounds users' decisions before, but never so much as now. For this flash to get such a high score must either mean that
A) it's funny even to people who haven't played MGS, or
B) most people have played MGS
I've never played MGS, and I can't for the life of me see how A) can be true because the humour seems to require a familiarity with the game. A lot of the humour is also somewhat crude. As for B), I never thought that Metal Gear Solid was THAT popular. Seriously, a 4.45/5.00 batting average and a 9.40/10 review average are simply astonishing. Congratulations, I suppose - I have no idea how so many people find this appealing but you deserve credit for making something that nearly everyone (except me) seems to enjoy.
To anyone reading this review - watch the flash, you'll probably love it. I'm honestly baffled as to WHY you would, though... I guess it's just one of the mysteries of the universe.