Wut. You've been on this site, yeah? We've got quite a bit of Western incest games here.
If you're talking about Western pron vids, just go on P*rnhub.
No need to search for anything. You should see a few incest vids just by going to the home screen.
I don't count Clickbait that has nothing to do with incest.
And that is what those videos are.
Same goes for all those "incest" videos where somehow magically the same daughter keeps having different fathers
As for games?
Unless the game has actual progression it doesn't deserve the word.
Progression as in Mother gives birth to siblings, which can be seen (birth scene), those kids then go kindergarden, school etc. then Dad shows interest in all kinda stuff that violates any and all rules, the kids start fumbling around, and player Control sets in once the kids reach proper age (to not make it all too insane).
Just being shoved start characters into the face and them being labelled this/that just doesn't do it. Because mother/father/son/daughter basically are just their Names then.
Nah, it has to be as true as possible, preferably with patrol cars driving thru the family's neighborhood, and hints that someone got arrested for exactly what "Dad" is thinking of doing.
Or better, stoned to death by the neighborhoor watch.
That's what makes incest cool:
It's not only sick and disgusting and gross and wrong and any and all bad adjectives, but breaks any and all norms, and basically ensures the end of your genetic lineage if you do it, since your descendants gonna be full of junk genes.
There's a reason after all why products of incest tend to eat human meat.
Hell if I could play as one of the mutants in Hills Have Eyes - also good example for incest done right - I wouldn't even focus on the sex part probably, and just have dinner.