In chapter 4, what does it mean that Dill is described as "as good as his worst performance" and his "worst perfomance was Gothic" in playing the Radley drama in To Kill a Mockingbird?
Dill is a good actor when the children act out different parts of Boo Radley’s story. Gothic refers to a supernatural element, so Dill can act scary parts well.
When the children get together during the summer and act out Boo Radley’s life, or other plays, Dill always plays the villain. He is so good that he could even seem tall if the part required height.
Dill was a villain's villain: he could get into any character part assigned him, and appear tall if height was part of the devilry required. (ch 4, p. 27)
Dill is particularly good at Gothic scenes. He can do what is needed for the dark and scary roles, since Gothic stories have many supernatural elements. To Kill a Mockingbird has several Gothic elements, including reclusive monsters like Boo Radley and many important scenes that happen at night.
With the Finch family, Dill finds a home. He is more than willing to be the scary character in the Finch children’s play. He enjoys being the villain, and playing the Gothic parts.
In chapter 4, Jem comes up with the Boo Radley game, where they reenact scenes from the stories and rumors they hear about Boo Radley's life. Scout plays any designated females roles in their "melancholy little drama" while her brother plays the main role of Boo Radley. Dill is the most talented actor out of their group and Scout describes him as a "villain’s villain" and says that he could play any role assigned to him. Dill particularly excels at playing roles that require him to act like a Gothic character and he is able to imitate the terrifying actors he routinely watches at the picture shows. One of Dill's favorite movies is Dracula and he apparently draws inspiration from such horrifying films, which explains why Scout says, "He [Dill] was as good as his worst performance; his worst performance was Gothic" (Lee, 40). Scout essentially means that Dill is an excellent actor, especially in roles related to the Gothic genre.