A cover of Queen's Bohemian Rhapsody was singled out for particular criticism.
"Watching his thin sketch of a voice being plastered over the original was a bit like seeing an upturned smile drawn onto the mouth of the Mona Lisa. With crayons," wrote controversial critic Simon Sweetman.
Williams obviously read the review, taking to his verified Twitter account to make a personal attack against Sweetman.
He called him "Sweatman," and branded him a "baby eater" next to a photo of the critic holding a baby up in a record store.
Fans seemed to agree with Williams, taking to Twitter to lash out at Sweetman's review.
Williams performs at Vector Arena in Auckland tonight.
- nzherald.co.nz