I give 3 for "effort." I don't men to be so harsh, as this is a good idea, if maybe not very polished. I have several complaints about my game play experience...
1. My soldiers, on return trips, will sometimes suddenly attack their own if I send them at that time. This doesn't always happen, but in the instance of the level where it is the first time facing two enemies, I had seven troops after they had none. I had three by the time I had taken out their many bases.
2. There is no directions on how to do so, but I can't seem to get anything better then the basic rifle. I have upgraded my bases to no avail. It changes nothing.
3. The enemy should get their own versions of these "upgrades" as you play along. I went with range, mining, and damage upgrades. The only time a troop died was when his comrades shot him (see above).
4. The upgrades seem to go too fast. While I realize they aren't big upgrades incrementally (for instance, the range only helps a few centimeters on the screen, but the map just isn't that large after the third upgrade) they just are too powerful.
Don't get too upset, as I think that you have a good thing going here, but I would have liked some "terrain" features, as well as a larger map. For a simple, yet intriguing game, you did okay. I would love to see you continue your work, as I think you have a good creative mind.