The ending in the book was way different too.
Wheels
I understand most of the book was from a different angle. In the novel Rambo apparently killed a large number of police and soldiers, while in the film there were only a few killed indirectly from Rambo's "nonleathal" actions.
If I recall, the closest the film Rambo came to directly killing a policeman in the film was shooting at Teasle through the roof in the closing scene.
It's been a while though.