This is a fun game and a great concept but It needs MAJOR work.
So far these are the things I noticed and these need addressing.
1. Unit cap is reached WAY too soon, there are times I'd hire one unit and my unit count goes up by one, then on my second unit it went up by 2, 4 on my third and then 5 on my fourth unit, what's worse is when i reach my cap I'm fighting a HUGE swarm of monsters and i am killed off very quickly. Many of the Unit upgrades you spend gold on do not seem to get applied properly as many monsters can still one or 2 shot a fully upgraded Warrior, Paladin or Dwarf.
2. Magic doesn't work alot of the time, What I mean by this is when I press the numerical key for the spells often times the spell does not go off when I press the shortcut key and i'm stuck trying to revive or heal multiple characters at once. Also please change the spells radius marker, you make single target spells like Heal, Revive and Thunder bolt look like area of effect spells when they are single target spells. The Heal spell should be Area of effect because of how clustered all the units get. Also most spells when you upgrade them do not perform as they should, many times at high levels for an example the revive spell will only bring a unit back with like 10%-75% of max HP.
3. maps are WAY too small, most of the harder maps are really small and rely on swarms to win as opposed to slowing down the players units with size and multiple bases.
4. I would like to see better control of the units, like being able to have them stand still while you form assault teams or form a defensive perimeter around your kingdom to guard your tax collectors and mages.
5. Also the Zealot often dies very fast for an armored unit, and often times his skills eat up his HP when he should have an MP bar, Necromancer abilities don't seem to work well on enemy units and Archers are Overpowered because the majority of enemies are beasts.