At first glance it looked exactly like Doom 3 but edited with a new trailer.
Graphics seemed to be exactly the same, despite stating that it
"offers greatly enhanced graphics".
Only real difference seems to be that it includes also the previous doom games, and that the flashlight is now armor-mounted and not an item you equip instead of a weapon.
John Carmack:
“Today, the full experience has been enhanced and extended to be better than ever, and is delivered across all the platforms with a silky smooth frame rate and highly responsive controls. New support for 3D TVs, monitors, and head mounted displays also allows players to experience the game with more depth than ever before. We think shooter fans everywhere will love it.”
The term "silky smooth frame rate" (as well as highly responsive controls) is usually (with no known exceptions in fact) used to describe 60 fps.
EDIT #1:
Related video: http://www.youtube.com/watch?feature=player_embedded&v=vIkrQK60N-4