A simple example is the password to open the gate in Nancy Drew: The Final Scene. It's randomly determined. Each time you load the game, you get a different password. There are something like 350,000 possible variations.
I haven't seen a visual novel try something like that, probably because it'd be difficult! But I was thinking about writing a visual novel called Love on the Oregon Trail a while back. Is there some kind of template I can make for that? Like...
- The man is [widow/single] and the woman is [widow/single]. They are [same age] or [man/woman] older by [1-4 years]
- They [want to be together and are kept apart by circumstances/are total strangers who are forced together by circumstances]
- The villain is [man's relative/woman's relative/third party]
- The villain wants to keep them apart because [they are nasty in general/they think the other person isn't good enough/they want to date the other person themselves]