Imperialism II: The Age of Exploration/Gameplay

Resources
Imperialism 2 is largely a resource management game. This table lists the raw materials available in the game and what materials or game concepts they are needed for.

Among the manufactured materials, lumber is used for building roads, ports, ships, and forts. Paper is used for worker training and civilian units. Iron is used for building roads and ports. Bronze is needed for most military units until steel is researched. Level 1 and 2 forts require bronze, level 3 requires steel. Trained workers require sugar, cigars, or hats, depending on their level of training. Cash is needed for research, military funding, and trade.

Capital Placement
The first task in a new game is to choose the location of your capital, unless you set the option to place it automatically. The capital can't be placed in hills, mountains, or swampland, and must be either on the coastline or on a river. The main objective here is to maximize your initial food production. Choose a location that is adjacent to as many tiles of farmland or ranchland as possible as these tiles are immediately developed at no cost. River locations are an additional advantage as they provide one unit of fish per tile. A secondary objective is to place the capital near forests and fertile hills. You need to quickly establish a steady supply of timber and wool to expand your economy. Having those tiles near the capital means less roadbuilding before these tiles can be developed and transported to the capital. A tertiary objective is that you get free scouting for minerals in hills, mountains, and swamps and development to a level one mine if minerals are found there, but since minerals are not guaranteed it's not worth sacrificing food for.

Early Exploration
Buy an second and third civilian explorer as soon as you have the paper to train them. Have them explore all mountains and hills in your home province, starting with those closest to the capital. You're mainly looking for iron; coal will be useful later and copper is useless unless paired with tin.

Send at least two carracks to look for the new world. You'll need to keep one in port if you want to trade. Once they discover the coastline of the new world, send an explorer to scout those provinces. Start with deserts (looking for diamonds) and mountains (for gems, iron, coal, copper). Finding diamonds or gems may give you help in deciding which New World provinces to invade first.

At higher difficulty levels, you'll start with a tech disadvantage. In this case, you'll also want a spy early since to help your research programs.

New World Conquest
It's important to secure some territory in the new world. Certain resources are unavailable in the old world, and others may be scarce. Unlike in the old world, new world provinces don't have forts and can be invaded without having to declare war first. Have one carrack establish a beachhead on the province you want to invade. Three knights can handle most of what you're likely to find (usually a few bowmen, clubmen, and spearmen). If the knights take damage, let them recover for one or two turns before tackling a new province. Take provinces until you get the announcement that your new military units start with a medal. After that, save the cash by only attacking provinces that are mineral rich or strategically important.

Capital provinces tend to be better defended but are absolutely worth taking. Capitals have a port. Ports normally cost 5 lumber, 5 iron, and tie up your engineer for several turns. You probably can't afford that now, and you can't transport any riches you find in the new world without a port. Capitals have town development and contribute materials even if you haven't researched town development yet. Develop 4 forest tiles in a new world capital and you get lumber on your transport screen with no labor cost. Conquered capitals have a few thousand dollars in their treasuries that you get to loot. That should pay for your march to the next capital.

Key Technologies
Here are some of the critical, game-winning technologies. Depending on the circumstances, you may need to vary from researching these directly, but these are good techs to set in the goals screen.

Galleons: This is the most important ship in the game. You start with three carracks. Your fourth ship should be a galleon. Your next 20 ships should be also galleons. In times of peace, galleons have twice the cargo capacity of carracks. In times or war, they're the most powerful ship until ships of the line are researched. If you get involved in an early war, two galleons blockading your enemy's port will cripple his shipping (unless he also has galleons) and likely also his economy allowing you to finish him off at your leisure. You may even get some free ships out of it. Even once you get ships of the line, don't upgrade galleons. Ships of the line are better militarily, but have only half the cargo capacity. Since you pay full cost of the new unit, you can have a ship of the line and a galleon for the same price as the upgrade.

Town Development: This tech allows towns to produce materials directly at no additional labor cost. This is huge, representing a potential 50% increase to your economy. Four of a resource in any province gives a free unit of the material made from that resource once the town is upgraded with a builder. Additionally, a unit of steel can be produced from two iron and two coal. If you're lucky enough to have copper and tin in the same province, two copper and two tin gives a free unit of bronze. This usually needs the roads transport two and the level two mines to be fully effective. Whenever possible, plan your development as to maximize the benefit from this technology.

Horse Artillery: This is the first light artillery unit and is critical to any old world military campaign. Lancers and pikemen can't take a fort unless backed up by artillery to either shoot over or breach the walls.

Light Artillery: The steel-based upgrade for horse artillery, these serve largely the same purpose. Once you complete this research project, upgrade all your horse artillery units. If you're ready to complete this, check out your neighbors; do any of them have any rich provinces you want or is getting too powerful? There will never be an easier time to wage a war then when you have this and your enemy doesn't. Just use your superior range to shoot over his walls and take out his artillery before they can fire a shot. Move fast; he may only be one or two turns behind you technologically so the goal is to cripple him before he can balance the scales. Obviously this works in reverse too, you're in a dangerous position if your opponents have this and you don't.

Military Units
Military units in Imperialism 2 are roughly divided into three categories: infantry, cavalry, and artillery.

Infantry are not very useful until the later tech levels when they get rifles. Then light infantry can draw opportunity fire from enemy artillery so that your artillery can advance safely. Medium and heavy artillery are not as useful at drawing fire, but have more firepower which is important if enemy cavalry try to charge your vulnerable guns. Before rifles, use cavalry instead.

Cavalry units are useful at all tech levels. They are the fastest units and usually also have good defense and melee firepower. They can be used for drawing opportunity fire. They are also great at maximizing casualties by charging the enemy's fleeing units. Damaged units that successfully retreat can heal and bother you again in a few turns, so use cavalry to chase them down and either kill them outright or trap them so they surrender.

Artillery have the most range and firepower, but weak defense. They're great at attacking forts (and defending them), but are vulnerable and need to be protected from return fire. Light artillery is the only artillery unit worth building. Heavy artillery is crippled by lacking the ability to move and shoot in the same turn. This means they have very limited use on offense. They can be used on defense, but forts are cheaper, don't require food support, and upgrade automatically and at earlier tech levels. So just build forts wherever you want heavy artillery. Bowmen are almost useless at early tech levels and completely useless once light artillery units are available. Don't build any and disband them if you already have any.