Great to see, thank you for making this video. I thought it was hilarious that you built so many drones. They're terrible in combat, so in the UI I will change their name to scout.
Also, the reason the other army was just standing around and not killing you is because the default AI is minimum level. I liked your fortress too.
The thing with the fortress is that basically it should have worked but you picked one of a small number of places on the map you could be up against the edge and can't wall off the other sides. The walls are ideally like a plus sign around a unit. The up, down, left, and right will be shielded by a building at any distance but the corners of the map are not safe ever.