Spoilers abound, so stop reading if you haven't seen it yet.
The beginning of the movie started promisingly enough. Okay, over the top action sequence on Krypton, but I liked Russell Crowe's Badass Jor-El. Moving on to Superman's beginnings on Earth, the introspective moments and the slowing pace helps. Then finally Clark becomes Superman, and then... shit explodes everywhere. Superman seems completely unconcerned about the tens of thousands of people that are dying from his battle with Zod. In the Christopher Reeve movie with Terence Stamp as Zod, Superman had the sense to draw the bad Kryptonians away to the North Pole. Here, pft, he just doesn't care.
Also, this is the first time the people of earth has seen Superman. They have no reason at all to trust him, especially not the military (since they were playing that angle). There were no character-establishing moments where Superman doesn't just save the president, he also pulls kittens from trees (see Superman: The Movie).
Finally, didn't Superman practically lead the army to his mom's house where his spaceship was hidden? Didn't they figure out his identity already from there?
Frankly I'm tired of huge flaming spectacles with no substance to them. ALIENS! BIG BATTLE IN THE CITY! SPACESHIPS! SUPER-POWERED BEINGS! That describes every final act of most major tentpole summer movies I've seen in recent years - Transformers, Avengers, even Star Trek. Now this.