If everything in the game is related to the 28th July, there is a small error in the timeline. Compare the story of Matthew DeFoe in 5 Days a Stranger and in Trilby's Notes. Indeed, in 5DAS, Matthew DeFoe disappeared the 28th June 1821 when in Tribly's Notes, it happens the 28th July 1821.
Trilby is named after the type of hat that he wears.
Although the game is available for free, you can download a Special Edition if you donate $5. Next to the game, that release includes author commentary, an extended ending sequence, the full soundtrack in midi format, with composer notes and prototype tracks, and the Books of Chzo in word format, with additional chapters.