I was kind of underwhelmed when I first boot it up. Coming from Sons of Liberty, Snake Eater felt less responsive, had lower framerate and lower IQ. It was ofcourse much more detailed in return. But I felt the camera had run its course, Splinter Cell was already a thing and SE was much more dense than SoL Its when I bought Subistence that I could really appreciate this game.
I think objectively speaking, this might be the best MGS game even. It has a jungle backdrop, it takes place during the Cold War era, it has the best storyline. Big Boss was more bad ass than Solid Snake.
And the attention to detail is insane considering this is PS2. Foliage reacts, rain removes footprints. The End fight is a good example of all this detail culminating in this fight. You can use the flora and fauna to stop him, rain will remove his tracks which you need to adjust to. And, you can even kill him prematurely.
MGS4 was an incredible downgrade compared to this one.