okay, let's back up and look at the big picture of star wars novel vs film.
here are the differences between ANH, and it's original novelization/adaptation (from wookiepedia):
During the battle aboard the Tantive IV, the stormtroopers drop through the ceiling, rather than charging through a door.
Before Leia Organa is captured, she kills two stormtroopers, instead of only one.
Before Grand Moff Tarkin and Darth Vader enter the conference room scene, there are eight Imperial Senators and officers around the table. In the film, there are only seven officers. During the scene, Vader uses the Force to summon a cup from the table to his hand.
Skywalker's X-34 landspeeder has an enclosed cockpit unlike the open cockpit seen in the film.
The hilt of Skywalker's lightsaber is described as having a jeweled hilt.
In the novel, Tarkin is present during Organa's torture. In the film, Organa does not encounter Tarkin until she is taken to the Death Star's Overbridge.
Chewbacca is described as having bright, yellow eyes.
In the cantina, Skywalker is haggled by a trio of individuals. Kenobi cuts a smaller alien in half and cuts off the arm of another. Ponda Baba is described as having multiple eyes.
Jabba is described as a fat biped with an ugly, shaggy skull and jowls. His scars are said to be a sign of his ferocious reputation in combat.
After the destruction of Alderaan, Vader reports that Alderaan had possessed defensive systems "as strong as that of the Empire."
In the novel, Obi-Wan does not feel Alderaan's destruction through the Force.
Stormtrooper TK-421 is identified as THX-1138.
The officer commanding the detention block is killed activating an alarm rather than drawing a blaster.
When the gang dives into the garbage chute, Han Solo dives in before Skywalker.
The garbage chamber's number is 366-17891 instead of 3263827.
During the Battle of Yavin, Skywalker, Biggs Darklighter, and Wedge Antilles are all in Blue Squadron; in the film, they are in Red Squadron. Skywalker also makes two attack runs through the Death Star trench. When Skywalker learns that Darklighter had been killed, his eyes begin to water and he reflects, "'We're a couple of shooting stars, Biggs' he whispered huskily, 'and we'll never be stopped.'
At the novel's end, Organa gives Chewbacca a medal.