Error+or+Style?

=How do you decide whether the following is error or style?=

= When Chris caught you in tackle tag, he lowered you to the ground gently, so that you lay in his arms for a minute, looking up at him through the tangle of yellow hair, the green lawn wet below you. Sticks in your back. Blue eyes laughing at you. Wild knowledge in your heart. (The Power of Grammar, 64) =

If this is style, why is it effective? If it is error, why is it ineffective?