Usable in a wide variety of settings, HANDCASTLES allow for modular rules to be added to campaigns.
The mission timer reminds me of XCOM and games of the genre where a strategical layer is put on top of "simply" executing the missions. Taking a step back is always good in order to have a different perspective on your missions and see their consequences and where you will be headed next.
The "In Between Missions" section adds a need to keep track of resources gained during missions but if it's okay with you, it really adds a sense of progression to the setting.
To be honest, I'm now a complete fan of the baba yaga cottage.