I think not having all of the skills available is a good thing. thered be no challenge and youd not have to pick a strategy. at least the way it is it can provide a small challenge.
Many of the upgrade components are bugged. for instance if you get the artillary army skill and use it from the start it doesnt apply if you upgrade the tower. Same with Acid poison for wyvern tower, etc. great concept game but needs ironing out a little more. lots of potential.
its insanely glitchy. cool theme and setting along with the complexity of the combat along with abilities. I couldnt play it properly due to the team command and selection bugging out.