15 minute Bioshock Infinite Trailer: What is to come?

At IGN, a 15 minute gameplay trailer was released to show what would come from the game. Here is what I saw and thoughts of those things.
Click Here to watch
First thing I noticed is that you get a companion that stays with you, and has many "plasmids." She helps the main character by warning him when there are enemies, and creating things out of thin air. One example of this in the video is when she tried to make a turret to destroy an enemy airship.

Second, I noticed that the PC has a voice. I don't not enjoy just an arm with a gun, but I like when the main character takes a part in the conversation. It gives a story more depth.

Third thing I noticed was the size of the world. In the original Bioshock, you were in enclosed spaces where your best weapon for survival was the shotgun. In Bioshock Infinite, you come out of the water and up in the air with great distances between you and enemies.

Last thing I noticed was the new weaponry. In the video people were shown many types of weapons. In Bioshock, you could hold all the weapons at the same time. In Infinite, it looks like you can hold only 2 weapons at a time, like the Halo games.

I can't wait for this game to come out in 2012.