Personally, I love the premise. It reminds me a lot of District 9, which I loved. Setting an quasi alien invasion in modern day South Africa is brilliant. I don't think that setting an alien invasion in an old western is that far off.
Sure, the premise is a bit rediculous, but it's no Ninja Assasin, Crank, or Transformers. From what I've seen, it looks like a good production. We can't really know about the story until we see it so I won't make any judgements, but the plot points I've seen so far (mysterious alien bracelet thing, gives user various powers, use said powers to destroy aliens) workable even if they're basic.
I'm not writing this one off yet.