There is a new version up with an upgrade system for units and a third ressource (Terrazin). You can boost atackdanage, health points or Movement speed. I played 3 games so far with the new system, i think its quite nice. Ok, it adds something i call the "stressfactor" to the game, what not everybody will like, but also opens a whole new bunch of tactical possibilities.
Becaus of the new upgrade system, the rare cards have become a lot less powerfull in my opinion, and you can really pull of soime wicked combos (Immortal with elite training and improved health Oo).