Really neat idea and execution! I wish I was better at it.
I thought I had a good strategy, put all the turrets on the left and hold my position on the right, always repairing the closest window. It sort of worked sometimes, but not well enough to keep me alive for long. I'm sure winning at blackjack is the key to success, but I'm always in such a panic mode during the building period that I barely manage to get the turrets in place.
I like the art, everything is stylish but clear. The music is appropriately tense.
Also I appreciate that I'm playing as "the shakiest gun in the West" since it gives me an excuse for being a bad shot!
The only thing I'd note is that I'd like to be able to reload manually. I know I can just fire off a shot wildly to empty the chamber and trigger auto-reloading. That's probably a better strategy since there's a chance it'll hit some vamp as it wanders in, but I couldn't get into that headspace and, instead, I pushing R as if it was going to do something. :)
[Edit] I forgot to mention the scoreboard! A great inclusion, I did nearly as well as a Taco!