With a trill, the 19-year-old warble rapper YNW Melly can make a death knell sound like a lullaby or inflate a petty breakup into an epic tragedy. At the age of 16, Melly, from an unincorporated spot along Florida’s eastern shore, started uploading his pastel trap songs to SoundCloud, becoming a small-town sensation before spending a year in jail for firing a gun near a high school. Behind bars, he started to take rap more seriously, writing his best song, “Murder on My Mind,” a stunning prison log that morphs during its second act into an intimate exchange. Melly’s power comes from converting solemnity into enthusiasm, making sweet things of sour situations.

Melly exists a world away from the rap of Southern Florida, specifically the lo-fi, bass-boosted behemoths of Broward County. His music is less actively aggressive in sound, if not content. Sometimes his ghoulish melisma resembles Trippie Redd’s, while some of his flows and melodies feel indebted to Lil Uzi Vert. He’ll dip in and out of melodic phrases like Young Thug. A true child of SoundCloud, he is most interested in hitting the right note. Last year, on his debut mixtape, I Am You, he turned casual terrors into buoyant songs. He interpolated Chris Brown’s “Say Goodbye” for a tune called “Slang That Iron” and sometimes veered from home invasions to amorous gestures. There is a tenderness to his singing that even lends a fragility—a beauty—to his threats of violence.

We All Shine sounds more polished than I Am You, slightly more braced. There is an enhanced fidelity, giving his voice more shape and tracing his runs with more precision. At points, he sounds like he could open for the B2K reunion tour. He sings about hundred-round drums and twerkers, on songs like “Rolling Loud,” with the same passion that R&B heartthrobs use to profess their love to their sweethearts.

But while he was smoothing his tunes, his writing lost some bite. None of the songs here match the heights of their predecessors: the vivid imagery in “Murder on My Mind,” the sobering introspection of “Mama Cry,” or the rousing salvos of “Virtual (Blue Balenciagas).” His collaboration with Kanye West, “Mixed Personalities,” should be a banner moment for an unsigned artist like Melly; their duet characterizes lovers as bipolar for simply ignoring their calls, and it is almost painfully unremarkable. (Kanye, who announced that he was bipolar by scrawling it on the ye cover and called the disorder his “superpower,” is dismissive of it here.) He’ll occasionally wander backward into a clever idea (“I just found out a new ingredient to death/I’ma give it all ’til it ain’t nothin’ left”), and he’s capable of dressing up some pretty bugged-out images. The most interesting thing he does here is write a diss track for his bank.

We All Shine is a regression in his development as a storyteller. “No Holidays” takes his most poignant jail revelations from “Murder on My Mind” and flattens them out until he’s rapping about jacking off in his cell, lining up for lunch, and wearing Gildan T-shirts. His observations from the inside come across as mundane. To be fair, jail by its very nature is mundane, but his potential hinges on his ability to bring a touch of the extraordinary to ordinary circumstances, to sing black and white into color. Previous prison dispatches imagined all Melly was missing on the outside, but this tape lacks that outward-looking, illustrative quality.

Melly was originally pegged as a serenader, though reports of his balladry have been somewhat exaggerated. He hasn’t penned anything quite like “Trap Queen” or “I Be U,” and the closest he gets to romance is offering to “lend” a city girl his love. But there is a warmth to his best music that feels sentimental, and it is there that We All Shine is transporting. The infectious “Curtains (Burtains)” reimagines Young Nudy flows with more robust croons. “Control Me” has the same 1990s R&B bounce as some of the most catchy Kamaiyah songs, with choice words of post-millennial intimacy: “I would never look on your post or your messages,” he sings, as if reciting wedding vows. When YNW Melly is on, it seems like he can make any banal string of words pop. Listening closely to We All Shine, however, proves just how much his writing must be the glue that holds it all together.