Truly amazing.
But now I am a veteran of MGS:Twin Snakes, and I can honestly say it was one of the most satisfying experiences I have had on the Gamecube!
This is not to say that other action games are bad...they just aren't the same. The story of Metal Gear is a dense and mindblowing epic which spans decades, and has a very large cast, and players don't get even close to understanding the depth until they have experienced the other titles. I only know this because I have seen the third game played through, and done a bit of the second one. There is conspiracies taking place with characters that are close to you, and even at the end, there is more to explain. The graphics are a huge improvement from the PS1 title, and the reworked cutscens are too outrageous to not enjoy. It's like watching The Matrix, except Solid Snake is a far more interesting character than Neo, and played by a better actor to boot. The final chase is probably my favorite of all of these bullet time littered moments.
The ranking system confuses me though, as this was my first time playing, and I used the M9 tranquilizer throughout on the genome soldiers, tranqued Ocelot, Mantis, and Wolf, and still had ten kills at the end of the game. Pretty strange since I ended fire fights with snoozing soldiers at my feet. This isn't a problem so much as it is confusing for me as a player.
I didn't enjoy the small bit of back tracking here and there, such as the PAL key at the end, and seeking a sniper rifle to fight Wolf on the communications tower.
A small hint for everyone...to hell with the PSG-1...get the PSG-1T from the nuke building B1. It will save you a lot of time that you won't have to spend working your way back to the Armory to get the same gun. It's just as easy to use the PSG-1T.
I will close with this: if you have yet to play this game, or you have only played it's PS1 brother (twin), then pick this title up before the price skyrockets.