The Official PlayStation Blog had a live Q&A chat with Naughty Dog's Creative Director Amy Hennig and Co-President Evan Wells. Here's what we know about Uncharted 2: Among Thieves based on that chat:
* The single player campaign is going to be longer than Uncharted: Drake's Fortune.
* The final list of Trophies is still being finalized and it looks a few MP trophies will be included.
* Local multiplayer is not supported.
* Enemies has classes. The lightest classes of enemy will allow you to perform hand to hand combat much the same way it was in the original game, but the medium classes enemies will counter your attacks requiring you to dodge before you can finish them off. Then the heaviest class of enemies won't let you melee them at all.
* A special Cinema mode will allow players to play back any of their matches and view it from ANY angle. Players will be able to upload those recordings and screenshots.
More facts in the article.