1) Flash is a jock, school athlete. The movie portrays him as intellectual (being in the decathlon team) and nothing athletic about him.
2) Liz, why is she there, doesn't do much for the plot. Could have done without a love interest. And Pete's 1st crush was Gwen.
3) No spider sense. It failed him on several occasions in the film; Ned discovering his identity, Vulture capturing Spidey when he was chasing the van, Aunt May also discovering his identity, Shocker catching him off guard and punching him at the school car park, to name a few I can remember.
4) Did he keep calling Aunt May by her first name only? What happened to "Aunt"?
5) Why do the 2 reboots have Spidey using mechanical web shooters instead of being a power he gained from the spider? His creating the web liquids in chem class is..
6) The greatest advice Pete recalls in time of trouble is not "with great power comes great responsibility". Instead, it is "if you're nothing without the suit, you don't deserve it". Or whatever Tony said to him. And his greatest mentor is Uncle Ben, but in the movie, it's Tony.