Well, I'm quite a ways in now, and it is packed with awesome, such as a short flashback sequence of the initial entry to the base in MGS1, a battle with Crying Wolf in the same place as Sniper Wolf, then receiving her rail gun (which kills geckos in one shot), Otacon telling me I need to change the disc at the disc changeover point in MGS1 right after, and then piloting REX, treating GECKOs like ants and then kicking the **** out of Prototype RAY. And all that in one chapter!

I also really like that the stealth isn't forced. You can simply choose whether you want to sneak around (which has been improved as well) or be a badass, guns-blazing type.