This is a very nice looking and highly addictive game. I liked the pixelated art style and font. (is that an existing font, or did you make it yourself? If the former, what's the name?)
My only problem is that I had a lot of trouble figuring out what the various units did. You said in another comment that the icons denote gameplay mechanics that didn't make it in, but are there any differences in the units? I found that 6 pointers in the first level could lose to much cheaper units, but later armies consisting of 6-pointers kicked my ass. So, do they area damage or something?
And what exactly are the other differences? It just bugs me that my best run (39) happened when I was just trying whatever, and that all attempts at executing a pre-planned strategy died sooner :p