The Amazon reviewer is right that these "Twenty Views" of the Christ Child are not made more understandable by their Biblical subtitles, or for that matter their main title, either. One senses ntothing especially religious, devotional, mystical, or child-like in Messiaen's various episodes. The idiom is nowhere near as fierce as the Amazon reviewer warns, however. There is little obsessive repetition, and the music is actually more often soft than loud. It's colofrful to say that the piano is made to "sing, speak, growl, clang, crash, and scream," but many of the episodes are gently reflective.
Messiaen has invented a variation on Debussy's discovery that the piano can be released from formal structure into free expression, color painting, and mysteriously shifting moods. However, Debussy employed a much wider harmonic range. Messiaen has some favorite chords and exotic effects, including his famous birdcals, that are displayed across a wide range of rhythms and fragmented phrases.
You'd never expect that such a long, rather opaque work could become a hit with audiences, but it has. I msut admit that Messiaen's idiom becomes hypnotic, and the simple forms, plus the absence of much dissonance, makes it easy for listeners to sink into the music.
Peter Serkin was a pioneer in the Vingt Regards, and although later recordings have shown wider dynamic ranges and fiercer attack, his inward way seems perfect--this CD is a classic of modern music performance.