The same exact shades of two colors (blue-grey and peach) are used throughout the film. Blue-grey is when Sarah is feeling more lucid, and peach when she is less lucid.
Following "Joshy" and "The Little Hours", director Jeff Baena wrote the screenplay with a detailed outline and let the cast improvise their dialogue.
Alison Brie and Molly Shannon also star in Promising Young Woman, though they don't share any scenes in that film.
Although all three only interact individually with Alison Brie in this film; Meredith Hagner, John Reynolds, & Angela Trimbur all star in Search Party (2016).