3.5/5 Overall not bad few quirks that bugged me to no end though.
First thing that bugged me to almost no end.
You shouldn't have to win a battle upgrade the tower, only to have to go win another battle to unlock the troop or spell or boost Etc. You're already putting in the work to get the thing to be able to BE upgraded, now you're adding double costs to things which can put strain on a player more late game as you may of picked a far less optimal setting without knowing.
Battle Units: This just doesn't seem to do much really or at least it didn't feel like it as I got further in a rank 10 unit still craps out almost as fast as a rank 3 unit. At rank 10 you should be creme of the crop able to handle quite a lot, though I felt like they just puttered out quite fast.
Having a retreat all button is a grand thing indeed and can be quite useful.
Problem comes in the form of having to click on each individual unit who is dying to retreat them before you lose a rank 10 or 5 etc and then you're at bare bottom again. Basically have a Low HP retreat button. Set it to 5 or something and all who are at it will leave auto with it's click.
FOR THE LOVE OF GOD. If I want to overwork my units, don't make me have to do it each and every single time I come back into the town. Keep them on overworked unless told otherwise it really slows down the pace and gets annoying having to click on each unit and click overworked while trying to make sure they heal and have spells etc.
Is there really a point to this dude being past level 5? At that point you build with plenty of time left to do things and yet he goes to level 10...Seems like a bit of a waste, perhaps some kind of passive boost to things when he gets level 10 to make it actually worth the investment?
Why are tsunami and tornado seemingly useless? Lightning you see results right away and it's animation is fast to the point allows you to keep going. Hand of god a little slower to boot up but still highly effective in quashing enemies, Meteor is the middle ground animation but it keeps going without you needing to do anything. Tornado and Tsunami on the other hand are slow...Don't see much result and overall are eh. Yet they cost to pick them up(refer to cost issues in above)
Those flaws aside, it's a pretty fun entertaining game. It last enough to keep attention through a playthrough of it or in my case most of a playthrough. With those fixes, i'd easily play it again and all the way through multiple times.