Like @Rob, I tend to lean towards the original as the better game.  Both games had the ridiculous waves of enemies, but the difference between DF and AT was ammo availability.  If DF, the better guns/ammo was much less common, and the player often had to make a choice: do I stick with my one-shot kill weapon with only five bullets left, or do I grab the pea shooter with ammo strewn about?  AT had all kinds of bullets lying about, which often made the battles devolve into shooting galleries.  Also, the puzzle elements of AT were much less common.  How many times did you need to use the journal in AT as compared to DF?  It was easy to forget you even had it.  And for a final gripe, I was disappointed in some of the ‘gameplay’ elements of AT.  One of the very first interactions with the controller is pressing a button to climb over a fallen tree, or up a small rock ledge.  Hardly the most challenging of tasks.  And how suspenseful was the ‘tight-rope’ section in the mountains, when you couldn’t fall off?  Missteps just caused you to fall and catch onto the beam, followed by another button press to stand back up.  It was underwhelming.

Enough bashing.  Thanks for the debate!