The first thing to know about this game is that it's really short, that said, there isn't much else that I had a problem with.
The AI was interesting, at points it seemed really smart, following me to hiding spots and flushing me out. There were also spots where I assume the AI couldn't reach so I would just be completely ignored while sniping NPCs all over the map.
The story was pretty good, maybe a bit confusing, felt like it was pulled out of the middle of another game.
This is the first Metal Gear I've played since MGS1, it was much better than I was expecting and now I'm really looking forward to the next game.