The last of the Louisville rapper's early mixtapes for his indie label, Private Garden, before he signed to Generation Now/ Atlantic, Gazebo captures the sound of Jack Harlow already leveling up. And it's not just about the sharpened focus that Harlow and producer 2forwOyNE bring to "Dark Knight," the punchy underground hit that led to his major-label deal a year later. It's about the creative growth and maturity that manifests in many ways throughout Gazebo, some of which may have surprised those who thought they had this upstart pegged. One is the overall coherence Harlow brings to this set, which he wanted to sound "like Louisville at night." That 3 a.m. vibe is as palpable in the opener "Eastern Parkway"—which borrows its name from one of the city's main drags—as it is in the propulsive "Dark Knight." Augmented by contributions by Willy Will, J. Reid, and Ronnie Lucciano, the production work by 2forwOyNE provides Harlow with a solid foundation of tight trap beats, moody atmospherics, and ghostly, fragmentary melodies like the kind that fill "Used to Be." Harlow's ideas about how best to create these soundscapes are fast-evolving, too. On "Routine"—an affecting rumination about hip-hop's impact on his life to date—Harlow's flow shifts between his ever-dextrous rhyming and early displays of the singing voice and more overtly pop sensibility soon to be heard on later hits. Elsewhere on Gazebo, he moves beyond the teenage brashness he exuded on his 2016 mixtape, 18, by showcasing a greater sensitivity. "Tightrope" is one of many tracks here that show the limits of his bravado as he ponders the challenge of maintaining empathy in a tough, cynical world and of keeping up the search "for something that lasts." Marked by the plea "I just wanna feel alive," "Maybe" is another sign of the melancholy side that's emerging. That said, Harlow also shows plenty of the charisma that got him to this point—along with the pleasure he takes in showing all that he can do.