Entertaining game with a nice idea
I really liked the game and played through it. The idea ("ageless" war) was quite good and pretty neat realised. The different Armys were really cool, and the upgrade system was thought through. I also liked the graphics, you can see that someone put some time into designing the game.
Well, I also think I played a very very similiar game before, but I won't let that influence my score.
On the other side, there is something that is definitly influencing the score:
the game balance. I noticed two major points:
Your "difficulty" ranking was 4%, 8%, 12%, .. until 80% and the survival mode should be 100% I guess. It really felt more like 1%, 2%, 3%, ... until level 16 with 16%. It then drops back to like 0% in the last 4 ninja levels, cause you only need buy one helicopter after another (the "magic" thingy :D) and the ninjas can't do shit against them, because they got no range ^^
But then come the survival mode! You have evaluated it with 100%, I would give it at least 300% in comparison to the other levels. This is not a bad thing, but the overall difficulty stays on the ground until it rockets into the sky with the surv mode.
So you should make the first levels harder, maybe you can put in some stronger enemies (like in the surv mode) and at the end of each "age" a boss-mob or something like that.
Still, overall very nice game. 8/10 and 4/5 from me.