Whoever seeks for hard core fighting will be served well here. Since that "you should add an invasion" the mission must have been changed - seriously. Without MASSES of spearmen I wouldn't survive. Though wood is precious and not available at the market.
At first, the Lord has to do a bloody job all alone. It's almost an RPG to find out the best course for him.
Then, after some failures, I learned how to make just enough wood to place just enough mines and quarries for gold and some workshops. During the course I bought dozens of spears.
After the first wave of invasions, every player should save the game. Save money for +5 good things. The eco requests will be achieved in addition.