I haven't played much of the rerelease, and I finally started playing it again. I got to omega base, and I noticed something strange in project labs: they changed Bruce Banner's voice actor. His voice is higher and he delivers his lines faster and in a different way. (Is it sad that I've played that level enough to notice?)
On an unrelated note, I also noticed they fixed a part of the minimap. Right after the gamma bomb, but before the control room where you shut it off, there's a room with beds on the side. In the old versions, the minimap showed it as two rooms set away from the aisle at different distances. On the rerelease, they changed the map to show one room, which is nice.