Being one of the gems of my childhood, you can imagine how surprised and excited I was to see this series pop up in the steam store. For those unfarmiliar, Stronghold is a sort of economy based midevail RTS. Esentially, you are given a set of different scenarios in which you have to use the resources in the varying enviorments you are given. Sometimes, these enviornments will help you get an advantage to your enemy - you may be located close to trees, which will allow you to get a quick start on building many essential things, such as food and weapon producing buildings. Otherwise, you may be given a disadvantage at times and being able to make do with what you have can make victory all the more satisfying.
In Stronghold, you need to think carefully about how you spend your resources. On one hand, it will be important to build a barracks so you can hold a strong and ready militia to defend against your enemy's forces. On the other hand, in order to raise a decent army, you need to keep your peasants happy and in your castle. This requires keeping your grainary stocked with food, being able to have enough industrial buildings to build farms to keep peasants fed, and other mechanics.
To be victorious, you have to carefully plan out your divison of resources - it is equally important to keep your peasants populous and happy and to have a strong defence to wane off enemy attacks, as one good strike can land a once prosperous land in ruins, and you very vulnerable to further attacks. All in all, I would strongly recommend Stronghold to anybody new to the RTS genre. RTS veterans would probably enjoy playing this one, too. There's nothing quite as satisfying as surviving a seige and being able to crush your enemy in a few swift blows.