My altered view of MGS4 now that I've beaten it.

[Impulsivity]

First off I have to say both on challenge and raw gameplay the best MGS game is by far, MGS the Twin Snakes for gamecube. Its basically just MGS1 but they added a lot of the better MGS2 features (such as aiming and better control) so you get the great modern MGS gameplay in easily the best game of the series in terms of raw gameplay and stealth action.

That said as a total package MGS4 is far and away the best. I would liken the series of games to a very well done trilogy plus a tangentially related story thrown in (MGS3, which was still great fun and brought in the awesome camo system) The first game has character introduction and more action since there's less to explain (1 really keeps you in the dark on most things), the second has a little less action (and the HUGE mistake of not letting you be Snake) and a little more story, and like Empire Strikes back, a barely victory ending. MGS4 does have a little extra in the way of cutscenes (ok a lot extra) but its amazing in how it wraps things up. If you played the first game and didn't find the Metal Gear Rex scenes awesome I have no idea why not.

@Rocketpig As far as the game being easy if you play on a lower difficulty level DON'T complain about it being too easy. If you wanted it to be harder (or in the case of boss level way harder) then don't play it on easy or normal. Friggin duh.

I also found the octo camo to be amazingly fun once I got the hang of it. For a real challenge combining octo camo and going for a low kill count game (using stun knife and tranq darts) is very difficult. That has always been the pinacle of MGS difficulty, the no (or limited) kill game. In the end though I found myself liking just about every part of the game, yes even the meryl holding off the endless frogs (yes I could have done without akiba part but I still felt a strong sense of wanting Meryl to live that kept the scene interesting, once again probably in part from remembering her in MGS1).

There are all kinds of little fan send offs that are great if you played the first ones too, every character more or less is back, the references to the earlier games, even obscure ones (like akiba being the soldier you own early in MGS1, the Metal Gear vs Metal Gear battle, psycho Mantis being back, and my personal favorite when Snake has the dream when going to Shadow Moses that takes the form of playing a section of MGS1). It was just great and engaging all around, beginning to end. Pick up the MGS 3 pack if you haven't played them, then play MGS4, its 100x better if you do. Its like watching Return of the Jedi before the other two movies, sure its good on its own but its way better if you saw the other two first.