I think you should add an invasion, it won't be a good challange to economic scenario if there is no an invasion. And it's not hard after all. What i have to do just get money from the grassland.
The guard in the recources is good idea, good job!
Map Design: 2
well this small map need more nature effect....
It's ok, try more....
(sorry my very bad english ;( >.< =( )