I assume it is why the critics and general audience adored and embraced TDK. It went beyond Heath Ledger's acting and the classic Batman-Joker clash.
In that line of thought, I want to admit something. Way back in '08, and before that, I couldn't care less about Batman. I didn't see BB, and I was looking forward to Iron Man, because not only I was a huge Marvel fan, I was also a huge IM fan. The only thing that interested me in TDK was the fact that both Heath Ledger and Christian Bale (my top two favorite actors at the time) were starring in it, and the fact that they were going against each other sounded pretty cool. But other than that, I didn't care much about it.
I remember when I first saw Iron Man, I was like "Oh man! That was awesome, one of the best Marvel films I've ever seen, way better than last year's SM3, FF2, Ghost Rider or whatever. Great film, I'm not sure something will be able top that for me in the near future.
A couple of friends saw TDK before me and they actually spoiled the ending (and most of the story for that matter), and I didn't even care. From what they told me, I wasn't really impressed. As I said, I planned to see it only because my two favorite actors were in it.
So I went to see it, knowing the ending, basically knowing all the twists in the film. I also didn't see BB before it, and I also didn't like Batman much. In fact, he was probably my least favorite superhero back then.
If someone had a picture of me during the time I was watching TDK for the first time, I would probably be starting at the screen with my jaw on the ground. I was literally stunned. Man I will never forget the moment right in the middle of the film, they had to change the reel - just when Batman breaks the glass and enters the mall on the Batpod... I felt so irritated that I had to wait for the film to continue, I just couldn't stay still on my seat. At that point, I admitted to myself, "****, that is good, that is really, really good!"
And the last 20 minutes? I realized I cared for a character I didn't even like before, and not only I cared, I cared for him more than I ever cared for any other character in a superhero film before. The action scene in the end, with the SWAT, that was very emotional for me somehow. Instead of thinking about the action, I was thinking "This is a man, who's dignity should be pummeled to the ground right now, who just lost the woman he loved, who is pushed to his physical and mental limits, and yet he runs around, beating SWAT officers, sacrificing his own reputation as one of the good guys, just so that he could save those people in time..."
And the ending? That awkward moment when you're trying to brush your tears away, while watching a Batman film, trying to make it look like something else, only to realize the person next to you is trying to do the same.
I got laughed at when I recommended the film to all my friends, they were like
"Really? You of all people? A die-hard Marvel fan who doesn't even like Batman? Wow, it must be really good"
Man I hope TDKR brings some of those feelings again...