As an XCOM fan this was a treat to try out. I think the addition of having to overkill the remaining damage is interesting, but I couldn't differentiate between health and armor.
I think the first thing I noticed that could use tweaking is not knowing how much of your movement bar was used for a given move. I would move somewhere and have too little movement left and be left open. It was also unclear to me why some melee skills wouldn't work, even if I was next to the enemy. Some skills didn't seem to work. The enemy turn could also either play out slower or have more information to communicate what happened. I would also appreciate if we could know the enemy's effective range so we can position just outside them and such.
Overall, interesting base and ideas. Would like to see how you develop the ideas and after some polish!