In this movie, if you watch closely at the Vogon's guns as they are firing at the Heart of Gold (on the planet with the people who believe the universe was sneezed out of something's nose,) while the Heart of Gold is lifting up, the gun's shots are firing towards the ship (which is above and in front of them), they are still aiming straight forwards yet the shots are coming out of the guns at an angle!

(Note: In the book, the guns are referred to a Kill-O-Zap guns.)