First off, Peter Parker doesn't have a goal in this movie. At first its to find out what happened to his parents, which isn't explained in this movie. After half an hour he now tries to control his new powers, in scenes that don't help the audience. In the original spider-man, Peter learned about his powers in a controlled environment, he didn't beat up innocent people on a subway train. It's nice to know no one on that train reported that a man beat up five people while climbing walls. But Peter learning his powers can't be an entire focus in the movie, so we kill Uncle Ben. This time it doesn't work because the only reason Peter let the criminal get away was because Peter couldn't get a chocolate milk. To get so upset that he couldn't afford a chocolate milk that he would let a robber get away with the stores money is a contrivance in every way. So for about ten minutes Peters new goal is to bring uncle Ben's murderer to justice, let the police can't link all these look alike criminals spider-man does capture with the man who did kill peters uncle. After a while he just stops doing this, with no reason! And there is still about an hour left, so what are we going to do now? How about introduce that main villain you've been promising us? The Lizard is horribly written in every scene he's in. Why does he go to so much trouble to knock cars off of a bridge just to tell one guy (who is never seen afterwords) that their vaccine isn't ready yet? Because we needed another action scene. After that they bring up that the daily bugle wants pictures of the lizard, a point that doesn't amount to anything, except the lizard finding out who spider-man is. For someone as smart as Peter Parker has been set up to be it was really stupid for him to put his name on the camera he was using to take pictures of the lizard.
The climax doesn't work for 2 reasons. The first being this is the same climax we've seen in about four other superhero movies. The second one being there are no stakes. Only half of Manhattan would be infected 8 minutes after the lizard started his chemical missile, decreasing the people at risk greatly. Also THERE'S A CURE FOR THIS!! You know, the thing Gwen has been working on for the past 6 minutes? Whoever gets infected can just get the cure shot into them afterwords, and as of right now there are only 10 people infected, so why waster your time trying to put the cure into the missile that will stretch half of Manhattan and only effect 10 people?!
Gwen Stacy's dad dies and tells Peter to leave Gwen out of this, and proceeds to still date Gwen. What a great way to respect someone who died protecting people! Don't watch this movie, don't waste your time with this movie, even Spiderman 3 was better than this, so just watch the Sam Raimi trilogy, at least those movies had effort put into them.