Source: Wikipedia, Imperialism 2 , available under the CC-BY-SA License.
Imperialism II is a turn-based 4X game, where you have to "eXplore, eXpand, eXploit, and eXterminate" in order to achieve victory. The game however focus on the economic aspect by introducing the concepts of variable worker productivity, variable terrain productivity, labor allocation, resource allocation and logistics. . . .
The game is won when any of the "great powers" (France, Holland, Spain, England, Portugal or Sweden) controls more than one-half of the Old World. Control over other countries can be achieved by conquest or by diplomatic means (influencing "minor nations" Denmark, Germany, Ireland, Italy, Scotland, Switzerland and even the "great powers", so they would finally join the player's empire), or most often a combination of the two. Control of the New World is not relevant for the victory condition.