It's a promising engine. The map and diverse ally and enemy characters is enjoyable.
The overall mechanics needs a little work as anchor rushes were an easy choice to push and maintain an easy attack force.
The last level gave the best challenge as your tower wall keeps my archers at bay while the enemy magi area of effect my armory into nothing very quickly. Not that its super easy to make another wave of archers / elf archers mixed with heal magi.
I found the grinding for power up purchases to be enjoyable as I only need to play a level 2 - 3 times to gain a decent amount of gold... which of course increases with the further levels.
I'll give this a 4 star rating as I enjoyed the 2 hours it took to get from one end of the map to the other. Tutorial could use some work... more lessons per mission. I really enjoyed the speed at which everything loads. Although I never thought of it till after I finished the game... I should have just dropped all my units at the back of the base... may want to remove dragging units and give a movement power up of movement increasing spell buff to replace this feature.
I'd like to see a lot more levels added in a final marketable version if this was the case... Look at Pocket Army in the itunes store for a good production quality of this very same style of game... minus the hero.