"Raising a character's flags" essentially means that you make choices that improve your standing with that character and which are more likely to put you on his/her route.This terminology is quite common even outside of visual novels in anime.Other highlights include the convention’s manga library, on loan from Otaku Anime of Concordia University and Doll Fest, an event to celebrate ball-jointed and Asian dolls.“Anime was introduced to North American audiences primarily at sci-fi conventions in the 1970s and 1980s, when someone would hold a small screening of Japanese anime,” says Marc Steinberg, an associate professor of Film Studies at the Mel Hoppenheim School of Cinema.They form a sizeable fraction of the Japanese market: the most popular have sold over a million copies, and they make up the majority of offline PC games in Japan.
A visual novel/sim game about life, love, and working in the entertainment industry.
Anyone familiar with dating sims and romance visual novels will recognize the term "flag" in that context.
In these games, when you are presented with choices which affect how the other characters view you and potentially change which route you go on, it's called a flag.
Bishōjo games are similar to Choose Your Own Adventure books in the way of narrative.
Where the game tells a story, but the player may make choices to change how the story flows. While in the Western industries, those games can be considered as visual novel, this Japanese market for Bishōjo games have its own growth unrelated to the Western world.