Thank you! Yeah, I tried to intuitively teach players about new mechanics without explicitly stating what it was. I'm glad that it worked and that you enjoyed your time with it!
Actually, I already have ideas for other systems to go alongside of what's here. One of the things I thought of was having like a screen with the town and various upgrade services for your different defenses. Like a blacksmith could improve the soldier's attacks or maybe a stable could improve the health of the cavalry unit.