Ships and armies can go into terra incognita at a higher rate of attrition. When possible, ships should carry troops to secure possible ports. Once natives have been put down, traders can be sent in if available to get a little income and pave the way for colonists. Over time, marginal European countries can become real powers through the use of new resources. Key to traders and colonist is the number of ports a country has and its religion.
Protestant countries receive extra traders and colonists as well as a bonus in producing explorers.
The downside of this is angering powerful Catholic neighbors and antagonizing the Holy See. All of this play is crammed into eight shorter historical scenarios such as the Thirty Years War, the Grand Campaign and a fantasy Campaign. You can play one of up to eight major powers. Files can be easily modified to play a minor power. Europa Universalis gameplay is not for everyone.