This is quite a nice start, and I look forward to the completed version.
The team colors image on the barracks and catapult unit are far too large.
I'm inclined to disagree. I think it's a fine style choice. To each his own, of course.
Kinda hard to critique this since I don't know what is still WIP and what's done. The Warrior's attack animation could use a little attention. He seems to lunge
through the target. The Armoury is multi-selectable, and the Void Stone has wooden armor. Not sure if either of those are intentional, but I suspect they're not. I guess you probably did intend for the Balista to have impact damage, but I can't be sure, so I might as well point it out. Plus, I'm pretty sure it's spelled "Ballista", unless maybe that's a national variation. The Void Stone also doesn't have any team color. I'm assuming the attack icons are still WIP.
Some of the units could maybe use some more variety in their textures. I don't know what rules apply to your undead, but real corpses aren't just solid gray, and adding some open wounds, dried blood, etc., could be good for the horror factor. Currently pretty much everything is gray: stone buildings, old wooden siege equipment, corpses, and so on. It might help to have some more "damaged" looking animations, like if one leg drags behind because it's broken.