The album utilizes a soul-influenced sound[3] and contains Little Richard's biggest post-Specialty single in "Freedom Blues", which broke the Billboard top 50.

[5] Richard then signed with Brunswick Records but clashed with the label over musical direction, leaving it the following year and turning his focus to live performance.

Appearing at the Atlantic City Pop Festival in August 1969, Richard "revived his own legend" according to David Dalton of Rolling Stone.

[5] Richard described the album as "the only thing I’ve done since I was back in the business that I think is really good", referring to his work since he ceased recording gospel music.

[4] Though many of the songs use twelve-bar blues structures like Richard's earlier rock and roll work, the arrangements are more informed by the contemporary soul and R&B music of the time.

[4] Reviewing the album in 2009, Kev Boyd of Fatea Magazine described its style as consisting of "blues-inflected R&B, hints of Sly Stone-lite funk, the occasional rambling instrumental and Richard's characteristic scream-singing".

[4] Esquerita, an R&B singer, songwriter and pianist whose frenetic performances and flamboyant stage persona influenced Richard,[13] co-wrote "Freedom Blues" and "Dew Drop Inn".

[14] According to All About Jazz, the song revisits "conventional Little Richard terrain: the patent scream, rollicking piano and booting sax solo of his earliest hits".

[16] The second side of The Rill Thing opens with its title track, a ten minute instrumental jam featuring Richard on electric piano.

[15] "Lovesick Blues", a show tune written by Cliff Friend and Irving Mills, is most associated with Hank Williams who recorded a country cover of the song in 1949.

[16] The album was preceded by lead single "Freedom Blues", which became a Billboard top 50 hit, peaking at number 47 on 11 July 1970.

Billboard described the album as a "stomping, swinging, soulful leap backwards in the rock 'n' rolling '50s with the Muscle Shoals gang".

Selvin praised Richard's vocals and the covers of "Lovesick Blues" and "I Saw Her Standing There", and deemed the album "a most significant chapter in the living legend of the greatest rock and roll singer ever".

[17] Among retrospective reviews, William Ruhlmann of AllMusic described The Rill Thing as "a convincing update" on Little Richard's earlier work, despite "the rambling ten-minute instrumental title track".