This faction idea is cool thematically, and it's fun to see another faction interact with the ruins. The visual design and board layout looks great as well. We playtested them last night and I have some notes.
1) We really liked the interesting new aspects they add to games by being able to take multiple ruins on one turn and being another faction that actually uses items.
2) Due to the current card draw rules as written, Horned Heights can stall easily if they somehow end up with no cards in hand and only 1 tower. There's no way for them to draw more cards and thus place more towers. I think you may have meant for them to draw 1 card by default, plus 1 per card symbol showing.
3) It was really difficult for them to score points. After 5 turns, Horned Heights had only scored 2 points and both were from destroying cardboard (so neither of the two "faction-specific" scoring abilities). This was partly because they didn't draw anything they could craft and 6-7 cheap items got crafted away quickly. I think there needs to be a mechanic to take other factions crafted items (similar to how Vagabond and LotH can take crafted items) because getting items is not only their action engine but literally their points engine, so they are doomed in a game with high-crafting factions.
4) They can recruit a lot of warriors, but their battle ability seemed very weak. Only being able to Ram AFTER the build step in the turn made it so that even when they cleared a space for a tower, they couldn't build the tower until next turn and by then other factions usually filled that space. I think Ram should at least be in the same step as Move, Recruit and Build. Since our Horned Heights never got any boots, they also could only battle once per turn max. It seems very fragile.
5) Items tend to run out by the end of the game, so it seems like Horned Heights will stall out and have very little closing power. If they try to score fast and jump ahead too early, people will destroy their towers and they'll lose all those items permanently. It felt like they needed a way to retrieve items that had left the game, or another way to score points. This is where having more battles would be nice; with no items to score points and only 1 battle per turn, our playtest of them felt hopeless.
6) Personally, I felt it was confusing to give a new name to every item (Banquet Hall, Turrets, etc). It fits thematically but it made learning the faction more complicated than just saying (Tea, Crossbow, etc) since those are the words we already know for those items.
7) Stacking items under towers fits the jam theme very well, but in actual gameplay it was too hard for us to see what was under there, so we ended up just leaving the items laying out next to the tower. I'm not sure if there is a fix for this.
I do really like the interesting design with using items, stacking on ruins, and only being able to attack in neighboring clearings. I hope you keep working on this idea even if you decide to overhaul the design, and Horned Heights could end up being very enjoyable to play (and have a chance at winning)!