“The 20/20 Experience–2 of 2” sounds like the direct sequel to an earlier Justin Timberlake album, but not the one you’d think. While it was recorded during the same sessions as the first “20/20 Experience,” it actually feels more like a long-lost follow-up to 2006 smash hit “FutureSex/LoveSounds.”

The dream-like soundscapes that defined so much of “1 of 2” are absent here, replaced by heightened tempos, producer Timbaland’s skittering beats and some seriously potent hooks.

In a way, this is an odd move. After all, “1 of 2” attracted a huge amount of attention for its romantic, sophisticated sound. Why abandon that sound so quickly, especially on an album with the same title as the one that introduced it?

Listen to it closely, however, and it becomes clear that this wasn’t meant to be another take on the same genre. Instead, it’s the yin to the first record’s yang– darker, dirtier, and closer to earth.

“True Blood,” a ten-minute-long monster of a track, is one of the album’s early highlights. And “monster” is the right word: in keeping with “1 of 2”’s penchant for oddball metaphors, the song uses vampirism as a metaphor for romance. (Yes, the title is probably a reference to the TV show.) It’s goofy, but it works, thanks in large part to the neo-“Thriller” production on display throughout. This is a track that you’ll hear at every Halloween party this year, and for good reason.

“2 of 2” isn’t as experimental as the first “20/20 Experience,” but there are a handful of moments where Timberlake and Timbaland bend the rules of pop music. The most out-there of these moments is “Only When I Walk Away.”

Over seven minutes and three discrete sections, “Walk Away” transforms from sleek blues-rock to digitized reggae, from sharp focus to blurred impressionism.

Not everything about “2 of 2” is as effective. “Drink You Away,” the weakest track of either half of “20/20,” is a misguided attempt to combine Timberlake’s signature sound with modern-day country. It comes closer to being good than it has any right to, but there’s just not enough common ground between the two styles for the song to feel natural.

The album’s less optimistic vibe also leads to a few clunky lines. Unfortunately, “anger” and “Justin Timberlake” just aren’t concepts that go well together. To be fair, though, JT isn’t responsible for the album’s worst turns of phrase. Those come courtesy of Jay-Z, who spends his guest verse on “Murder” complaining about Yoko Ono’s role in pop culture.

On what may be “1 of 2”’s most beloved song, Timberlake described a lover as “the other half of me.” It’s a fitting line: “The 20/20 Experience” is a project that’s been built around parallel structures since the very beginning, and “2 of 2” is its purest expression of that idea. The fact that it doesn’t really sound like its predecessor isn’t the point — this is that album’s evil twin, and it’s all the better for it. “2 of 2” may not be a 5/5, but it’s a fitting conclusion to one of 2013’s finest musical experiences.