Star Wars mostly plays with the sanitized violence of a blockbuster film. Characters shoot blasters at one another, fireworks fly, and occasionally a stormtrooper or rebel trooper falls down with an exaggerated "Argh!" It's so schoolyard-playful you expect to hear someone scream, "I got you!"—followed by, "No, you didn't. I dodged it."
While this fantasy violence is enough to make the film a PG affair, there are a few more intense scenes. Darth Vader chokes the life out of a rebel captain with an audible crackle of bone and tendon. In another scene, Obi-Wan Kenobi goes all back-alley surgeon and amputates an alien's arm with his lightsaber. Although these scenes of more intense violence are few and far between, parents should be aware of them.
Also, just think about how many people Luke Skywalker kills when he blows up the Death Star. Some of them were probably independent contractors, right? Seriously unsettling.