Good art style but no explanation and way too short to see what the full game would have to offer, but the core idea has promise :)
This game is the kind of game that needs a better tutorial than a simple "?" button below the screen.
I won against the computer and can't really say why. I understood the basic build walls around crystal stuff but all of the rest is unnecessarily complicated.
I mean... what were the red guys around my castle and the enemies castle? Was I supposed to kill the ones on mine side or on the other side? What was that troll that came at some point destroying my stuff? How do I know how much energy I use? I clicked 1-2-3 and saw no result of my spells.
To add insult to injury this is only a demo with really minimal content.