This is from the Imp II manual for those interested...
Comparison: Imperialism and Imperialism II.
There are many differences between Imperialism and Imperialism II. The items listed below are changes to the game that might catch Imperialism veterans unaware.
How to win.
The council of governors found in Imperialism is gone. Players win by controlling over one half of the Old World. Control can be obtained by military or diplomatic means.
Since the New World does not directly help a Great Power win, good players will tend to invest in New World development only so far as it leads to greater power in the Old World. This is the model for victory appropriate to the era.
Feeding Everybody.
Agriculture was a more important part of the economy in the sixteenth century than it was in the nineteenth. You will find it a very important element of Imperialism II. Your agricultural productivity acts to limit the size of your army, navy, and labour force. Everyone must eat a unit of meat (fish of cattle) or grain every turn. There is no canned food in Imperialism II, but raw foods may be stockpiled in your warehouse.
The Transport Network.
This area of the game probably changed more than any other. On land, every tile of road counts as a depot; so no depots ever need to be built. To connect a mine, for example, build a road from the capital into any terrain tile adjacent to the mine. It is still neccessary to construct ports in order to move commodities over the water.
Another important change is the elimination of land transport capacity. All items moving only over roads (or later, rail) move for free each turn to the capital. Anything that moves anywhere along its route across water must be transported in the cargo holds of empire's ships. The same ships are used for exploration, war, and trade, and are subject to hostile interception. Transport is no longer safe - at least across water.
One consequence of the new system is the reduced amount of player micro-management of transport. Your land connections arrive automatically. These commodities are displaye don the transport screen, but you do not need to order them to be moved. Of course, you do have to decide how many ship cargo holds to allocate to sea transport, how many to save for trade, and how many to patrol the seas of the world.
Exploration.
When the game begins one-half of the world is covered. In order to conduct trade, diplomacy or war with the New World you have to uncover it first. For peaceful relations you need to find tribal capitals. To invade the New World, any uncovered land will do. There are two effective ways to explore. A ship is placed in a coastal sea zone reveals all the coast tiles of adjacent lands. Once a coast tile is revealed an Explorer unit may be deployed to the New World. Explorers reveal all the terrain adjacent to their location.
Developing Minor Nations and the New World.
In Imperialism, developments outside your country did not have to be connected by road to a port. In Imperialism II, there is no distinction between development at home and abroab. a nation or Tribe can only trade or transport commodities that are connected within its borders.
the Merchant unit, who resembles the developer from Imperialism, can protect a Tribe from invasion by purchasing land from the Tribe. Once this is done, other Great Powers can only invade after they declare war on the Power who owns the land.
Riches.
There are now five types of resources that convert directly to cash when transported to your own country. All of them are found only in the New World. In most games you will need to find and exploit these riches as a permanent source of funds. In a game representing the colonial and mercantile period, there are fewer opportunities to make cash by selling commodities than was the case in the nineteenth century world of Imperialism.
New World Resources.
The special luxury resources of sugar, tobacco, and furs are required to produce consumer luxuries for trained workers. The level of training of a nation's labour force is limited by the amount of New World resources it can acquire.
Technology Tree.
In Imperialism II each monarch has the opportunity to direct his empire's researchers along particular research paths. You can craft your empire building strategies according to the new technologies you expect to gain. A technology tree is provided on the enclosed referance card.
Turn-Based Tactical Combat.
Tactical land combat remains an optional game element. If you choose to fight your battles in Imperialism II, you will find that the initiative system for moving and attacking is gone. You are able to move all your units in any order you desire and then watch your foe do the same. Additionally, melee and firing are now two different forms of combat. This means that in melee combat, the defender strikes back even on the attacker's turn.
Since forts and siege combat were critical in the Old World during this era, you will find artillery essential to your success. Non-artillery units can only fire at enemies posted along the wall, and purely melee (all those witha range of one) cannot attack a wall or any units in a fort in any way.
A deployment limit is applied to all battles. This begins the game at 10 regiments. If you gain the Nationalism technological advance this limit is increased to 12. A general present in a garrison or an attacking force increases this one additional unit for every medal earned by the general.
This limit in no way affects the number of units that may be stationed in a province. Extra units will not be deployed in battle and will retreat if the battle is lost.
Cost of Attacking.
Monarchs during the era covered by this game had an extraordinarily difficult time funding their armies, especially during offensive operations. While you are on the defensive, your troops require only food. If you decide to attack there is a significant cash cost. Don't declare war without a large cash reserve.
No More Goods.
Although there are more commodities in Imperialism II, the goods that were such an important part of the Imperialism economic model are no more. Players must balance the development use of a material like bronze or lumber directly against the need for cash obtained by trade. This new model seems to fit the earlier time period of the game. Players need to directly exploit the New World for riches instead of investing in the factories and mills at home.
Major Changes to Interface.
Although many screens are different, the two that changed the most are industry and the newspaper.
The Industry screen in Imperialism requred a mouse-click on each seperate production building before the players could give production orders. This is now combined on one screen with (up to) 10 production sliders.
The newspaper of Imperialism has been replaced witha Turn Summary which reports only events that are important to you. Random events, both good and bad, occur and are reported on the Turn Summary.
Addendum. (from readme.txt)
5. In the Tactical Combat section of the manual (pages 58-66), inadvertently no mention of the 18 combat round time limit was made. A combat round is a complete cycle of both attacker and defenders having the opportunity to move and/or attack with all units. If at the end of 18 combat rounds there is no complete winner, then the battle is considered a draw and the defender will maintain ownership of the contested province.
8. In the Morale and the General section on page 61, the description of the General's capablilities should also include his command bonus, which allows 2 additional units to participate in attacks. This allows for a total of 14 units in an attack. This combined with successfully researching Nationalism, allows for a maximum of 16 units (including the General) to participate in attacks.