Concerned 2: A Concerned Rip-Off: The Continuing Adventures of Gordon Frohman is a webcomic by Norman N. Black, which acts as the unofficial sequel to Christopher C. Livingston's Half-Life 2 webcomic Concerned: The Half-Life and Death of Gordon Frohman. It ran for 61 issues (however only 53 have been salvaged on here) from 2008 to 2010. The series ended up going on a long hiatus, and is currently defunct.
A second continuation of Concerned (in the form of a prequel) was proposed by When-Worlds-Collide2 on DeviantArt, under the title Concerned 3: The GoldSrc Years of Gordon Frohman. However only a four page preview is currently available.