Theory: Barthes' Enigma Code

This code refers to anything enigmatic or mysterious which may be present in the narrative. Use of the code is common because an enigma is often created by the text producer to keep the audience engaged. Better levels of audience engagement will evoke stronger audience pleasures. These range from satisfaction, sadness to satisfaction. 
Trailers are likely to have a layer of enigma because of their nature; they offer an audience cryptic clues as to the narrative, providing them with enough information as so to spark an interest which they pursue and go to see the film.

An example of a real media text which uses Barthes' enigmatic code
Alfred Hitchcock's Vertigo (1958) utilises the enigma code. The narrative explores themes of obsession and mental instability. A detective is forced into early retirement following the deaths of two people, caused by his fear of heights. He sees a double of one of these people, a girl, and connects her image with her deceased body. The enigma is situated in both the detective's (and perhaps the audience's) inability to differentiate between reality and fantasy.

Vertigo theatrical release poster by Saul Bass

Applying the enigma code to my coursework production
I have attempted to use the enigma code in my trailer by including close ups of the antagonist, but not revealing much about the mechanisms she uses to embody and do evil. At the beginning, I have included a voice over which poses questions in the minds of the audience.

Image from https://en.wikipedia.org/wiki/Vertigo_(film)