Paul Cornell, Martin Day and Keith Topping wrote of the serial in The Discontinuity Guide (1995), "For an eight-year old, this was the most terrifying slice of Who. Now it seems a little ordinary, a simple reworking of classic themes. It is unfortunate that the detailed jungle set is in such sharp contrast to the (cheap) minimalism of the Morestran spaceship." In The Television Companion (1998), David J. Howe and Stephen James Walker described Planet of Evil as "a wonderfully creepy story" with the borrowing of material from Jekyll and Hyde "done with such style and panache that the viewer, far from complaining about a lack of originality, delights in spotting all the familiar sources to which the writer and the production team are paying homage." They also noted that the antimatter monster, depicted only as a shimmering red outline, was "in all but name, the Id monster from the 1956 MGM feature film Forbidden Planet." Howe and Walker also praised the jungle set and the performances of Frederick Jaeger and Ewen Solon, but criticised Prentis Hancock's "poor" portrayal of Salamar.
