The album was preceded by a series of four EPs, released digitally and on 7" vinyl: 20 Odd Years Vol. 1: Avant (released June 2010), 20 Odd Years Vol. 2: Distance (July 2010), 20 Odd Years Vol. 3: Albuquerque (August 2010), and 20 Odd Years Vol. 4: Cenotaph (September 2010). The album primarily collects songs from the EPs, including a cover of Leonard Cohen's "Who By Fire". The album also includes two new songs.
20 Odd Years has received critical acclaim. Ross Langager of PopMatters gave it a seven out of 10 rating and called it "uneven but dynamic", complimenting Buck 65's "mix of subcultural influences" as "a dizzying, post-modern, multicultural stew". In consumer guide for MSN Music, critic Robert Christgau gave 20 Odd Years an A- rating, noting "Superstars Don't Love" and "Zombie Delight" as highlights, and commented that "Beholden to nobody's scene or purist myths, the Halifax-spawned, Toronto-based, Paris-savvy cult rapper makes beats his way—drum tracks of course, this is hip-hop like it or not, but with whatever on top, which here comes down to mostly female collaborators whose sonics subsume their considerable verbal input".