A Western Game. Maybe?

Today i was watching a film on the TV it was a western film i forgot what it was called but there was a duel and i thought i could make my game based on a western.

1st Idea:
Make the western town and have an enemy and have a timer to see how long you take to fire the bullet and then create different enemy level's. So it starts off easy and gets harder and harder.

2nd Idea:
Have a background of a western scene and your on a horse and the background moves as you move on the horse. You go past the desert and strange items like:

-Cacti
-Bank Robbers
-Trains
-sherif
All of these items you will shoot at on your journey out of town.

3rd Idea:
you go around the western town with your gun in hand and you are the sheriff and you need to get the trouble out of your town so you have to spot the trouble out. You have a time you have to do it in 2 minutes. You also get a score for the most people you get out your town.