Needs some tweaking, noticed a bug
Overall, a very fun game. One bug I noticed, when you start over sometimes your main base placement is considered illegal (all red) and you have to start the game over to get it to place correctly.
Also, the change in difficulty is nice. However the jump from nooblet to normal seems rather intense. I have only managed to get past the 3 green rockets once, and even then only made it to the next wave. It may just be me, but on easy the game was so boring I quit before I got to then end. So I think some tweaking is necessary to get that just right.
Otherwise a very solid, addicting game. Bravo!