There are technical criticisms of the album, which was recorded at a club in 1964 under primitive conditions. But Lewis' piano playing is so incredible I think it takes the ear of a professional music critic or sound engineer to notice the record's flaws, at least on the first listen. See Wikipedia's article about the album for details, but one complaint was that the band that accompanied him, the Nashville Teens (actually a British group), was hard to hear.
After I listened to the recording it struck me Lewis is a great musician; a visit to Wikipedia indicated that my opinion is in large company. Indeed, Lewis (age 81), the ultimate outsider, might live to hear himself hailed as one of America's greatest pianists.
It turns out that Lee was a child musical prodigy. He was mostly self-taught. His parents recognized his talent and mortgaged their farm in Louisiana to buy a piano for him. But his wild-man antics at the piano, coupled with his rowdy lifestyle, tended to distract from the fact that he's a serious pianist and a music pioneer.
He created a sound that is to American music what bouillabaisse is to Louisiana. One part rock 'n roll, one part boogie-woogie, one part gospel, one part country, one part jazz, one part blues, and one part indefinable but very distinct. As a musician once observed, every type of music that Lee touches on the keyboard becomes unmistakably his.
But for a long time it was the gospel music part that gave him trouble. As Wikipedia recounts:
His mother enrolled him in Southwest Bible Institute, in Waxahachie, Texas, so that he would be exclusively singing evangelical songs. But Lewis daringly played a boogie-woogie rendition of "My God Is Real" at a church assembly.
For that, he was expelled the next day.
From other remarks in the Wikipedia bio I wonder if he believed the Devil made him do it. At any rate, after he shot to stardom he did agonize over whether his music was leading his youthful audiences to Hell.
Later in his career he found himself able to play pure gospel music. But now let's turn the clock back to 1964, to a club in Hamburg that was about to make rock 'n roll history.