Points for originality!
I have to admit, I haven't seen a western themed game in a very long time, which is strange because I think it makes for fun gameplay. Anyway, I'll have to agree with the majority of the reviews by saying that this game is pretty redundant. The first two levels were fine, but the levels after them are just boring. The gameplay was pretty decent, I like Crimsonland themed games, so I did pretty well on this one.
It seems that when you pick up the ammo crates you seem to get ammo for the weapons that you never use. Also the mouse scrolling control is pretty useless in this game since it just scrolls the page down instead of switching weapons. Plus some of the enemies were a bit overpowered, mainly that darker skinned one that shoots fireballs. Maybe you could tune that down a bit?
Good game overall, It kept me entertained. Just add some more level diversity and you'll be all set.