Attempting to pinpoint the single feature that made Eminem the best-selling artist of the past decade is a challenging and nearly futile task. After all, there are so many layers to the guy that make him such an engrossing enigma. The man’s been called a gifted artist as well as sell-out; a clever poet as well as chauvinist pig; a skilled lyricist as well as troubled lunatic. But of the many labels stamped on Eminem and his career, there is one that has evaded him all along: mature.

In “The Marshall Mathers LP 2” (MMLP2), the rap artist from Detroit explores some of the deepest, most adult themes he’s ever dared to delve into in his 14-year career. With a few callbacks to his younger and more erratic days, the album also manages to be a balancing act between his eccentric raps and his calmer approach to storytelling — and it works.

Eminem has long been known to use rap as an outlet to settle feuds with his detractors. In some cases, he’s even settled scores with members of his own family — including his mother. This album reverses those feelings of hate and replaces them with self-reflection, and in some instances, sorrow. “Headlights” is the song that best captures those themes. With the help of Nate Ruess, Eminem abandons the harsh feelings of resentment toward his mother and instead chooses to offer a sincere apology. In the song, he calmly rhymes, “I went in headfirst / Never thinking about who what I said hurt / In what verse / My mom probably got it the worst.”

A similar theme of self-reflection is present in “The Monster,” a song which will no doubt be a popular radio hit thanks to the pop vocals of Rihanna. The song serves as a cry for help for the tormented artist as Eminem hints at regret for choosing a life that guarantees scrutiny, sleepless nights, doubts and loneliness — a life he personifies as “the monster.”

Given that this is a sequel to the first “Marshall Mathers LP,” nostalgia is pretty much expected in this 16-track set. From the get-go, listeners are treated to a follow-up of the infamous fictional story told in “Stan,” in which an obsessed Eminem fan named Stan loses it and kills his girlfriend and himself after feeling ignored by his idol. In “Bad Guy,” Mathers tells a similar story through the eyes of Matthew, Stan’s little brother, as he plots to seek revenge by kidnapping Eminem, locking him in the back of his trunk and ultimately ending his life.

Creepy? Yes. Insanely original? Absolutely. And when you think about it, that’s what we’ve come to expect from Eminem. Even though Mathers is attempting to change part of his act, it’s always a twisted but fun treat when we listen to the crazy antics of his alter ego, Slim Shady.

There are a few mishaps in the album, however. The lyrics of some of the songs are overly simplistic and lack subtlety. At times, we are told what to feel instead of being led to that emotion on our own. Some of his attempts of comedic rap also fall flat and end up being more awkward than funny. And unfortunately, there are instances where Eminem attempts to burst into song, shrieking in falsetto and in one case, starting to yodel. Stick to rapping, Em.

It’s not the perfect album, nor is it his most groundbreaking, but the “The Marshall Mathers LP 2” still proves to be one heck of an emotional and psychological ride. It’s that craziness, originality and willingness to publicly display his emotions that make him and this album so special. For long-time Eminem fans, that’s all we can ask for.

Rating: 4 stars