Well videogames are good for taking others premises and making an unlicensed scenario of it. So I would just copy and paste a few things together into a legacy storyline, then divide these up into scenarios/stages.
1. You start out as a man with good intentions but badluck. First scenario is a shootout you wander into, you fend for your life and try to survive a time limit. At the end, a popular and established business owner of the local town is found dead and the fingers point to you.
2. You make a run for it, the next scenarios play out as escapes and your own personal investigation. As you get close to finding the real killer, you're injured in a gun fight and apprehended by the local sherrif, who is basically your foil. The good man who can wield a gun, and was lucky enough to find himself behind the protection of a badge. Now this guy is sympathetic to your cause, but holds up the law.
3.You're under doctor's care arrest and held up in a hotel room, where a homely nurse comes to know you. At a certain point the nurse frees you and you run off to find the real killer. ANother escape scenario. Next scenario is a duel, where you find the real killer, but succeeding you killed your evidence. The nurse finds you and helps you escape with her.
4. You're out in the wilderness, with a woman who loves you and with a bullet wound. You make your last stand, this would be an epic fight/scenario shootout in which you survive, but then a duel which you lose to the sherrif. The nurse runs away from the scene.
5. Now you play the nurse, who is pregnant with a child unknowingly. You wander town to town, picking up the way of the outcast, having been the lover of an outlaw. You run into a couple of the blacksmith boys looking for fun, and you have to shoot them down. You then play out a 'at gunpoint order people around' deal, to get yourself a ticket to a big city.
6. In this scenario, it is post birth, and you are working as a saloon girl. You carry a small gun in your stiletto and are working to support your son. The law has finally come for you, after your dealings in the old town, and you have a shootout at the saloon. You survive and hop on a train.
7. FUCKING TRAIN SHOOTOUT. A true western must have this, a stagecoach or train scenario and this is it. You're escaping to the north and must gun down the bounty hunters after you. You survive and arrive in Alaska.
8. You're now the boy, and you know your family's legacy of being an outlaw. You enter intot he wildnerness where noone knows you. Here you must shoot and trap animals, and make trades with the local tribes. Here you build reputation amongst the populace and skills for survival.
9. You run across a woman that reminds you of your mother, her husband and some of her children were slain by the local natives. You exact revenge on her behalf in this scenario, infiltrating one of the local tribes and gunning them down.
10. You move further down the yukon river, with one tribe having a price on your head, and another tribe gifting you for slaying their enemy tribe. At this point I see the game as reaching an ending, but an open ended ending where you can continue to play, doing the survival things.
11. One of the open endings you can choose is moving to a local town and becoming sheriff and finally changing the legacy of your bloodline.
You could probably fit more scenarios in between some of the ones I listed. It's a copy of plots from old tv westerns that leads into a Jeremiah Johnson sort of deal.
