How can you do that? Once I know the story and have played through it for the various different endings, I get bored since I know exactly what's coming and exactly what each character says/does in situations.
I loved K1, but I got bored with it after I saw both endings as both male and female, and once I got through with a lot of the mods. Same with K2. And same with BG, BG2, FO, FO2, PS:T, etc. Once I've seen the ending a couple of times I don't see it as fun anymore playing through a game where I know what will happen.
I guess I just can't think of ANY game that has a huge difference in variety each time you play through. The good ones have some instances where you can play through different, but none that give me a completely new playing experience after having finished the game 3 or 4 times.