Very cool! At first the UI had me confused, but it's not unsurmountable - my second game went much better, and I was dispatching baddies like nobody's business.

Some notes:
- The mood is great: a camp in the wild west that will be under attack at any moment, and everybody needs to circle the wagons. Great choice to add sound/vfx this early in the dev process to reinforce it.
- Destructible terrain is strategically interesting - it took me a while to figure out that the enemy was also using it to get to me (not sure whether deliberately). And the scorched earth holes are a great touch!
- Wild west theme is great, and underrepresented. Then again I would say that, wouldn't I?

Some low hanging fruit:
- I would dearly love:
1. Mouse pan (maybe shift + drag?)
2. Zoom in/out with mouse wheel
3. A pause button! :D
- Fog of war currently looks like a glitch in asset loading, it looks like tiles have failed to load - see screenshot:
http://imgur.com/BBq7Shr- I couldn't figure various parts of the UI, or couldn't figure out where I can place the mine.
All in all, cool stuff! Right now it plays like a TD game more than an RTS, so I'll be curious how the gameplay will evolve!