When the game ends, the player either loses the game if he failed to properly win over any of the girls, or "finishes" one of the girls, often by having sex with her, marrying her (as in Magical Date), and/or achieving eternal love.
This gives the games more replay value, since the player can focus on a different girl each time, trying to get a different ending.
This can lead to confusion, as visual novels are considered a subgenre of adventure games and are not technically included in the dating sim genre.
While the two genres often share a common visual presentation, dating sims are sometimes considered to be more statistically based than the "choose your own adventure" style of visual novels.
Dating sims, or relationship simulation role-playing games (RS-RPG), are a video game subgenre of simulation games, usually Japanese, with romantic elements.