Steven Cohen’s review published on Letterboxd:
Opening with plain-clothes officer Frank Serpico (Al Pacino) freshly-shot and headed to the hospital, Sidney Lumet's Serpico then utilizes one of my least favorite cinematic mechanisms by flashing back to show his career up to to that moment. The result is a pretty episodic film in which Serpico is confronted with corruption, resists it, tries to bring it to the attention of someone important, fails, repeat. As with most movies he appeared in during the 70's, Pacino is excellent, but it's in service of a pretty bland and surprisingly annoying character - which I don't imagine was the intention. There is at least some value to Lumet's filmmaking - as Serpico encounters more and more roadblocks, the filmmaker imparts to the audience the same kind of suspicion and paranoia the titular officer is feeling. Otherwise though, Serpico is a bit limp.