Instruct: Classify the given review as either positive or negative.
Query: Metallica's first GREAT album

Metallica proved they could give variety in this album. Most of the songs are truly excellent, with incredibly impressive layers of music, especially in the classic instrumental 'The Call of Ktulu'. The songs 'For Whom the Bell Tolls','Escape', and 'Creeping Death' are some of the best metal classics to hit the 80s. 'Fade to Black' is one of my favorite songs. It's different stylistic approach could actually fall under the category of "melodious ballad", which is something Metallica didn't have until now. The other songs are O.K. to good, but I don't have to push the "skip" button like some other Metallica albums. This album and "Master of Puppets" are Metallica's most pounding pieces of work, and I highly recommend both to any die hard metal fan.