How does Dave Barry use imagery in Big Trouble?

Imagery:

"Roger, calculating with his nine functioning brain cells that the chances were better of getting food inside the house with the humans than outside with the Enemy Toad, left his surveillance post and shot a low-flying, furry missile, through the door opening into the family room."

"The killing was done with squirt guns. For the kill to be legal, you had to squirt your victim in the presence of one witness—but only one witness."