Although some virtual dating games are different, most dating sim games give you a certain amount of days to get into a relationship.
You must use this time to build your stats and grow your relationship with the guys and girls in the city.
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.
The technical definition of a dating simulation game, known as a romantic simulation game in Japan, can involve several technical elements such as a time limit, several statistics such as looks and charm which can be boosted through exercise, or an "attraction meter" which can increase or decrease depending on one's decisions.
Oh, and that's before we even get to the lavishly designed environments, beautiful animations and a great cast of characters. Might have made the top of the list but no support for keyboard controls. Creatures gain experience and level up from battling. You have to find seven pieces of a broken magic mirror hidden somewhere on a mystic island.