Incredible visuals, very nice and "dramatic" music, loevly concept. As others have said more action from the player could be game a bit (maybe debuffs on towers, to deal less dmg or freeze them for period of time) and that I got into never ending cycle of towers killing my guys and not having any way to come back.
Still the game brought back to me memories of Warcraft 3 custome maps which is great :D This feels like one of those concepts that could be pushed into full game.