[Doc Faustus]

First of all, the concept strikes me as similar to Happy Birthday to Me. Second of all, your dialogue is uninformative. Tells us nothing about the tone of the movie and says nothing about the character. So, there's no reason for a person to want to make this script or to watch the film if it's made. The key is to try an angle that has not been tried before, to give it interesting characters and provide a worthwhile mystery. "Who is the killer?" is something you find out in virtually every film, why did they do it, what secrets do they harbor, what secrets do the people who aren't the killer harbor, that's what would make the film unique. "Who" is the least interesting question in any mystery. And Bloody Party sounds like an English Dark Wave band from 1984. Watch more movies. Read more and get a better grasp on the English language. Listen to people talk. Who the hell says to someone "Hello, you are invited to my costume party this Friday at 6:30 PM. " If somebody called you up and said that, what would you think of them? If you get party invites like that, your friends are robots. And thirty guests seems like a ton of people. How invested can you get in thirty characters? Also, a mystery does not become a better mystery because there are a ton of suspects. It becomes a better mystery if there are interesting suspects or unlikely suspects. And lastly, saying that the girl's name is Sandra is not enough to make her a character people want to invest attention in. Think about the movies you enjoy. Do you remember any movie and think "I liked that movie because that guy's name was Greg"? Change how you see movies, or else your writing won't improve and you won't be able to come up with a good concept or a character worth liking.