With the release of "I Need U" and The Most Beautiful Moment in Life, Pt. 1, BTS broke onto the charts with a creative breakthrough, balancing red-hot rap with a heavy dose of sentimentality. Now the hip-hop-inspired boy band's new winning formula gets further perfected on the release's second act.

BTS Show Love for America, Fifth Harmony & Perform Live in Billboard Studios

The Most Beautiful Moment in Life, Pt. 2, which dropped on Sunday, once again sees the septet exploring a range of emotions. A similar blend to the sentimental passion from "I Need U" is felt on synth-laden tracks like "Butterfly," "Autumn Leaves" and lead single "Run."

In particular, "Run" employs has a subtle, lush feel even with the impassioned raps, making it a late contender for one of 2015's best K-pop singles.

The band plunges into the aggressive zone on "Ma City" and "Silver Spoon," where they deploy typical rap braggadocio that somewhat detracts from the complex maturity showcased earlier. But the zealous raps on album opener, "Never Mind," and closer "House of Cards," feel like some of the most honest performance the group has created to date. Both talk about the pressure and worries of being young and successful with "Cards" sounding almost like a cry for help at times.

Perhaps most interesting are the metaphors BTS uses throughout the set. "Whalien 52" likens isolation and feeling like an outsider to the still-undiscovered whale species who speaks at the atypical frequency of 52 hertz and has been dubbed the "the loneliest in the world." Meanwhile, "Autumn Leaves" could have been an eye-roll-worthy metaphor about fleeting love, but instead features smart, heartbreaking lines of "rotting memories" and how the BTS boys want a relationship to fly but instead it falls down -- as autumnal leaves do. It's these key, empathetic moments that prove BTS has something that makes them very clearly stand out from other new boy bands.

Since its release, Pt. 2 has charted high on U.S. iTunes rankings and is trending similar to the small number of K-pop albums that have entered the Billboard 200. Should BTS send their album to the albums chart, it'll be the first for a Korean artist who isn't from SM or YG Entertainment labels -- both of which are considered the two largest in South Korea. Check Billboard early next week for final chart numbers.

Stream the album on Spotify and listen to a preview of the tracks in an album highlight medley below:

