I logged in about an hour and a half into Bioshock Infinite. I'm loving the new setting and story. No longer are you confined to dark corridors. Colombia is in broad daylight. The game has added exploration segments. I must have spent the first hour just listening to people's conversations, playing games, watching old videos, finding audio logs and searching every nook and cranny for money. There's so much going on around you that it's amazing. People are singing, children are playing in water, people are performing magic, there's carnival barkers, etc... The game is beautiful on top of everything. The first time I walked out into Colombia I just had to stop and look at everything.
The combat is pretty much classic Bioshock, you have a gun in one hand and use your abilities with your other hand. You can only have four abilities on you at a time, depending on what clothing you are wearing. Standard issue fireballs are in the game but now you can also set them as a trap on the ground. Possession is pretty cool. You can take control of mechanical objects with it. Use it on a turret and it will mow down enemies for you, use it on a vending machine and it will give you money. Soon you can possess humans and once it runs out they will commit suicide, hurting everyone near by. They added a grapple hook to swing around some environments and you can land on top of your enemies.
The story is what will have most people hooked. Colombia is formed by a religious fanatic that decides to break away from the US. A civil war soon breaks out in the city. Everyone is looking for the false shepherd, who happens to be you. Your job is to escort Elizabeth out of the city. You get to deal with some heady stuff like racism and political drama.
Those are my initial impressions. Long enough?