Much is expected from those to whom much is given (or, in other words, with great power comes great responsibility). That's the theme that pushes Spider-Man to take on the much stronger Lizard, with some concerns about his abilities, since nobody else really has the ability to stand up to the bad guy. Teamwork and collaboration play important roles, and love (familial, romantic) is a big theme of the movie.
Plenty of super-powered comic book-style action, including cars getting thrown off bridges, villains throwing heroes through walls, and assorted other mayhem. A mugging leaves a shot bystander bloody and dying, and Spider-Man's first crime-fighting efforts target other muggers, who are clearly outmatched and beaten badly. An NYPD assault team tries to take out both Spidey and The Lizard, using high-powered weapons that leave the web-slinger injured and bloody. The villain impales a cop with his long claws, leaving the officer critically injured. Some bullying among high school students.
Some flirting, and a few romantic kisses.
Infrequent swearing includes "ass," damm," "hell," "suck up," "oh my God," and the euphemistic "Mother Hubbard," used as an expletive. Some insults -- "stupid," "loser," etc.
Tie-in to vast quantities of related merchandise. A few scenes feature people searching the Internet on Microsoft's Bing browser and looking for medical information on WebMD.com. Several Sony products also get prominent placement, as do Nike shoes.
The villain injects himself with a powerful drug that turns him into a giant lizard.