1 direction dating sim
While the genre started in the 1980s, arguably the first dating sim to make it big is Tokimeki Memorial, first released for the PC in 1994. Due to its popularity, the game been remade multiple times (Tokimeki Memorial: Forever With You, Tokimeki Memorial: Densetsu no Ki no Shita de, etc.) and has been ported to multiple systems (Game Boy Color, Play Station, Super Famicom, mobile phones, PSP).
There have been multiple spin-offs (such as puzzle games) and multiple adaptations (such as an anime, Tokimeki Memorial Only Love.) Aspects of dating sims have been transferred into modern non-dating sim games.
Ends can be fairly bittersweet: a good end can involve the couples in a long distance relationship or a deathbed confession of love, but it does involve the couple getting together.
In most games, the relationship between the avatar and the potential suitor is measured in a meter.
Other options are flash games, which are less focused on characterization and are hosted on websites such as Newgrounds.
Katawa Shoujo is described as a "a bishoujo-style visual novel set in the fictional Yamaku High School for disabled children, located somewhere in modern Japan." .
The game plays with the expectations of genres: aside from the obvious change in expectations (you date birds), the game is very self-referential and plays with tropes inherent in video games.
Hatoful Boyfriend shifts into a fighting style game during one potential suitor's route, and the second half of the full version turns into a dark, espionage thriller.
Despite Western thought, dating sims are not necessarily pornographic.
In fact, pornographic dating sims are a sharp minority in commercial dating games.