Vladimir Nabokov, 1962. A 999-line poem plus a delusional commentary. The novel as game.
From Wikipedia
Pale Fire is a 1962 novel by Vladimir Nabokov. The novel is presented as a 999-line poem titled "Pale Fire", written by the fictional poet John Shade, with a foreword, lengthy commentary, and index written by Shade's neighbor and academic colleague, Charles Kinbote. Together these elements form a narrative in which both fictional authors are central characters. Nabokov wrote Pale Fire in 1960–61, after the success of Lolita had made him financially independent, allowing him to retire from teaching and return to Europe. Nabokov began writing the novel in Nice and completed it in Montreux, Switzerland.