Finally Rich is Chief Keef's major-label debut, but truthfully, there's not a whole lot to distinguish it from the free mixtapes he made while on house arrest at his grandmother's place in Chicago's Washington Park neighborhood. Those tapes, first passed around among southside high-schoolers, were what landed the now-17-year-old rapper his Interscope deal, and apart from a few random A&R'ed guest spots, the label appears to have stayed out of his way.

That's a good thing. Chief Keef's music sparked a lot of arguments this year. His youth, his rapid rise, and his association with Chicago's epidemic of gun violence made him 2012’s flashpoint for discussions about what was wrong with hip-hop. But he established a simple sound that proved powerfully effective and addictive, and he also showed that it was a sturdy enough blueprint to support multiple songs. If Waka Flocka Flame woke up tomorrow utterly drained of the will to live, he might sound like Chief Keef -- all the unilateral forward motion and aggression, none of the audible joy. Young Chop's crisp snares and hi-hats mimic Lex Luger's (minus the tricky syncopation) while Keef mutters through a thick wall of processing.

There's nothing to add or subtract to this sound that could substantially improve it. Fellow Chicagoan Kanye West found that out the hard way when his Michigan Avenue makeover of "I Don't Like" was given a public dressing-down by Young Chop the day after it hit the web. Finally Rich benefits from some professional tweaks in the mix, but otherwise leaves Keef's sound untouched. And in addition to succeeding on its own terms, it proves that Keef has a lot of potential-- much more than his detractors might have hoped.

Based on a simple four-note earworm, the hook on album opener "Love Sosa" has the feel of something sung under the breath, and after hearing it once or twice, you'll probably find yourself doing just that. There's an unquantifiable line separating the maddeningly catchy from the simply maddening, and Keef has a natural knack for walking it. "Hallelujah", also produced by Young Chop, is one the album's more involved productions: Its blaring horns gesture towards Waka's "O Let's Do It" over Hammond organ licks that feel smuggled out of Houston rap. "Diamonds" has a similar feel, with gunfire, horn and string stabs, and a manic carnival-ride synth line all rolling out like evenly spaced 8-bit Donkey Kong barrels.

"Hate Bein' Sober", the album’s forthcoming single, is the catchiest moment and perhaps the most pop-focused song Keef’s ever made. It features 50 Cent, who sounds at home for the first time on a pop-rap hit since "I Get Money". Out of the handful of big names on Finally Rich, 50's appearance makes the most intuitive sense: Keef built his mystique, in part, on the idea that he was back from the dead, and 50 was the first rapper to overtly sell himself as an unkillable Terminator-like figure. His patented sing-song sloganeering sounds current again here, maybe because Get Rich or Die Tryin' came out when Keef was in elementary school and is part of his basic musical vocabulary.

Speaking of which: Chief Keef isn’t a lyricist. At all. His lyrics on Finally Rich are almost entirely composed of rudimentary gangsta-rap boilerplate, which he treats more like a graffiti bomber than a rapper, tagging his beats with slogans meant for maximum impact and minimal scrutiny. If there’s anything the odd jumble of industry rappers who show up on Finally Rich share, it’s this casual approach to lyrics. French Montana, who pops up on "Diamonds", is most famous thus far for literally inventing a word he didn't even say. And Wiz Khalifa fails to make an impression (as usual) when he drops in on "Hate Bein' Sober".

Some of the material filling out Finally Rich is already a year old, including the ubiquitous "I Don't Like" and another of Keef's earliest YouTube hits, "3Hunna", which now sports a Rick Ross feature. The album feels, promisingly, like a progress report on Keef's developing voice rather than a forced "arrival." This has downsides, as there are amateurish moments where some intervention might have been welcome: "No Tomorrow"'s vocals barely match up with the beat, while "Laughin to the Bank" takes a bassy "HAWH HAWH HAWH" vocal hook and flogs you into submission with it. It feels specifically designed to make older rap fans massage their temples.

But there are also hints of where Keef’s sound could go next: "Kay Kay", produced by K.E. On The Track, is gentle and pretty, built from rolling piano and airy synths. And "Citgo" is as close to an uplifting song as Keef’s ever written. Produced by Young Ravisu, it floats on new age synths while Keef sings a warm, sweet melody. The lyrics are still riddled with violence, but the ugliness of the sentiments don't survive the sunlight of song's major key. It's not a redemptive moment, exactly, but it is a transformative one. "[My sister] thought I was going to be some kind of motherfuckin' screw-up or something," Keef says on the intro to "Ballin", in a clip taken from an interview. "They thought I was going to be like, bad all my life…I gotta job now, I gotta daughter too." On an album single-mindedly devoted to painting Keef as pitiless and cold, it’s a brief glint of the dimensions this ruthlessly effective album barely touches on.