I won't go into any plot spoilers, so don't worry. From start to finish, I loved the game. Yes, the cut-scenes are long and can be kind of campy at times, but hey, it's Metal Gear. You know what you're getting into with this fifth entry (in the Solid series alone). The gameplay has been well refined, and its more fun by virtue of it's game mechanics than any previous MGS. Pretty much every aspect of the massive and complicated series narrative is explained and neatly tied up here, and there are some pretty big surprises, as well.
It was just awesome, and I'm looking forward to another playthrough sometime on a higher difficulty setting, and some Metal Gear Online action. Hopefully I can sort through all the crap Konami wants you to register for just to play the online mode (which sounds cool, though it remains to be seen firsthand).
It will be interesting to see if Konami wants to continue the Metal Gear franchise somehow, but hopefully if they do it will be with Kojima's blessing and guidance at the very least.
I could think of some cool scenarios both within the MGS3 through MGS4 time period and beyond, possibly featuring as the lead role The Boss, Big Boss (another MGS: PO seems like a certainty at some point), Ocelot, Raiden, or even Solid Snake himself, in the years between Solid 1 & 2, in setting up Philanthropy... it's a rich mythos, with a lot of possibilities.
Addendum: To round out my week plus of Metal Gear mania, I put some time into MG Online, downloaded the awesome (and free) MG Database on PSN, and watched what must have been around 2 hours of 'making of' features on the limited edition's bonus blu-ray, as well as listening to the game's soundtrack at work.
MGO seems pretty cool. It definitely has a more measured pace than an FPS. I wish the characters were a little less generic-looking, but the game is fun, and the Drebin Point system carries over from the main game, meaning you can select your load-out at the beginning of each round, plus tweak your character's skill bonuses in various areas. I'm not one to pay a whole lot of multi-player stuff, but I want to spend some more time with MGO. I guess I'm not ready for a second play-through of the game, but not ready to let go entirely, either.
Konami did something completely awesome, redeeming themselves in my eyes for the major hassle that getting into MGO was. They gave us the kick-ass Metal Gear Database, which is kind of like a giant Wiki covering all of the canon entries in the series from the MSX2 games through MGS4. It's a great help in understanding the series extremely complicated lore. I got it and spent the next couple of hours reading every entry I could to answer my own questions, and for the most part was satisfied. I'd still like to know how and when Solidus was created/given birth to. I made sure to click on every single entry, though there were a lot I didn't read, to get 100% in the database, but as far as I can tell, I didn't unlock anything special.
For once, I am completely happy with the bonuses in a game's limited edition. The soundtrack is a nice bonus, but the documentary blu-ray is absolutely killer. My favorite part was the half-hour or so look into Kojima Productions during the making of the game. I don't know why, but I kind of envisioned Kojima having his own big cushy office. What he really has is more of just a corner cube a little nicer than all the rest. It's also cool seeing all the people who do the art and all the other stuff, and them hashing out problems and differences of opinion when making the game. The other features on the disc were great, too. Getting to see all the voice actors blew my mind. I'm pretty sure Vamp's VA was in Pulp Fiction, and Raiden's VA is totally not what I'd expected. The stuff about Ryan Payton was interesting, too.
How can MGS be so awesome? I'm going to try to track down a copy of MGS3 Subsistence so I have MG and MG2. I have the NES Metal Gear, but a) I suck at it, b) it's apparently drastically different from the MSX2 original. Plus, I played MGS3's normal version. I want to re-play it with the MGS4-style camera sometime. The Boss remains one of my favorite characters in the series, and the ending one of my favorite scenes, too.