Critical response
On the review aggregator website Rotten Tomatoes, 100% of 5 critics' reviews are positive, with an average rating of 8.8/10.
William Schwartz of HanCinema praised Jung Hae-in's acting, commenting that he "is sublime here, in a brooding cinematic role radically different from the romances he's better known for." He added that "D.P. is worth watching, not just by people curious what South Korean mandatory military service is really like, but anyone from any country who's seriously thinking about joining up."
Pierce Conran of the South China Morning Post gave the series a 4.5/5 rating, noting that "D.P. hits home with a story that spans the past and present, as it acknowledges that yesterday's problems can still be today's." He also praised the cinematography as well as Jung and Koo's "electric chemistry".
Greg Wheeler of The Review Geek rated the series 4.3/5, noting that "D.P. is a stunning Korean drama [which] takes an unflinching look at bullying, the effect it has on mental health and larger societal questions about the mandatory military service in Korea" and praising the series for its "impressive" cinematography and for the way it "explore[s] a very sensitive and prevalent topic in a raw, artistic and unflinching way."
In a mixed review, Hidzir Junaini of NME gave the series a 3/5 rating, commenting that "Kim Bo-tong and Han Jun-hee must be given credit for how this series tackles such extraordinarily difficult and tragic subject matter with compassion and sensitivity", and praising the "uniformly excellent performances, splendid cinematography, addictive pacing, and intrepid commitment to shedding light on the appalling culture of bullying in the military", but criticizing the "weak characterization [of the] three main leads" as well as the "ludicrous escalation of events during its climax, which suddenly turns a fairly grounded show into a melodramatic action thriller."
On the review aggregator website Rotten Tomatoes, 100% of 6 critics' reviews are positive, with an average rating of 7.9/10.