A good strategy game, but the random luck of weak shots, critical hits, master hits, and repulses on special hits is annoying. That reliance on luck factor takes some of the strategy out of it. A less streaky combat system would improve it.
After playing through it as a veteran of other Tower Defense games, Easy mode needs to be tweaked. It was definitely challenging early on maps on Easy difficulty and I'd leak some creeps usually Red Soldiers that have some bullet armor.