The Pros:
Same gameplay we've come to respect from the first game; awesome "survival" aspects and thrilling fight scenes. Beautiful scenery and well-done character graphics. A post-apocalyptic stage is always a winner in my book.
The Cons:
The creators took extremely well-developed characters from the first game and made them unrecognizable. The game introduces new characters (which is fine!), but the original characters and their stories become buried and distorted.
Advice:
It's not uncommon for a "sequel" to contain an entirely new set of characters, completely unrelated to the original plot/storyline, while still using the same "world" or setting. They should have done that here.
The creators should have also allowed for alternate endings based on the player's decisions.
Overall Impression:
Intermixing the old characters with the new characters didn't work as well as they expected. Strange, uncommitted "backstories" that never actually added up made it difficult to believe the story Naughty Dog was selling.
The timeline jumps around like a bad movie... I found myself frustrated at the "progress" and was desperate to get back to what I felt was the "good storyline," which never seemed to happen.
I felt the holes in the story were too incomplete, the "merge" of storylines were too interconnected to the point where it made it unbelievable and forced.