The XGM installer will use your existing preferences if it can find them. It also makes several default changes: (1) Advice is switched on and set to low. (2) Advice is switched to text only. (3) The green unit marker arrows are switched off. (3) The unit upgrade sparkle effect is switched off. (5) Editable settlement names are switched on (left click on the settlement name at the top of the settlement info scroll). (6) Fatigue is switched off (the AI doesn't know how to manage fatigue). You can change these default settings by editing xgm/preferences/preferences.txt.

The Map

The map is based on the Mundus Magnus map by ngr. The map extends north to include all of the British Isles, south to include Ethiopia and Arabia, and all the way east to India, making it much more suitable than the vanilla map for representing the Hellenistic world. The map is big enough that you can now play the Seleucid Empire in all its sprawling glory, or play the as the Greco-Baktrians, holding out on the fringe of the Hellenistic world.

The map has 199 regions, including three sea regions, producing better naval AI behavior, and two un-capturable desert regions, producing betterAI behavior and historically accurate game-play. Map heights, features, and settlement locations have also been altered to produce better AI path-finding.

The Sahara has been unified into a single region, and some regions in out-lying parts of the map have been combined, while a number of new settlements have been added in and around Greece, including Thebes, Ephesus, Cyzicus, and Patras.

A land bridge has been added between Sicily and Italy, allowing armies to walk between the two regions, resulting in more release behavior by the Roman AI. An optional land bridge also connects Europe and Asia Minor near Byzantium, allowing for AI forces to invade Asia Minor from Greece, and visa versa.

Trade resources have been adjusted to represent the vast wealth traded along the silk road, and by sea from India to the Mediterranean world via Arabia.

Colonies and Culture

A new culture mechanism has been introduced using the religion mechanism from the Barbarian Invasion expansion. Populations are divided between three culture groups: Barbarian, Western Civilised, and Eastern Civilised. When you capture a settlement that belongs to another culture you can begin converting the population to your own culture by building a colony. This will cause unrest in the short term but greater stability and tax income in the long term. It will also make it possible to build higher level barracks in the settlement.

Building a colony takes time, involves considerable expense, and can seriously annoy the natives. When deciding where to expand, consider carefully whether you will need to build colonies in your newly captured territories. Expansion is always easier in regions that share your faction’s culture. If you do decide to colonise, make sure you are ready to deal with the ensuing unrest. Sometimes building entertainment or cultural buildings, like Theatres or Arenas, in advance can be a good idea.

Martial Law and Pacification can be used to impose an iron rule on newly conquered territories, but that control comes at a steep economic cost. To construct the Martial Law or Pacification buildings you will need to demolish any existing temple. Because of the high cost of maintaining Martial Law, or a Pacification campaign, you should demolish these buildings and return to a normal mode of government as quickly as possible.

Military Infrastructure

All factions can recruit basic garrison units from government buildings. Siege weapons are built in siege workshops. Chariot units are typically recruited from Blacksmith buildings. Otherwise almost all recruiting is done through the culture specific Faction Barracks buildings, and the culture independent Auxiliary Barracks buildings.

Each culture has its own type of Barracks building, which can be used for recruiting faction units. If you capture a settlement belonging to a different culture, then you will not be able to recruit units from the existing Barracks buildings, so demolishing the existing barracks is usually a good idea. To recruit your own faction units you will need to start building your own military infrastructure. To build higher level Barracks buildings you may also have to establish your own colonies.

Auxiliary Barracks can be used to recruit native unit types from the local population. The units available will depend on the region. Auxiliary Barracks are not culture specific, so if an Auxiliary Barracks exists in a recently captured settlement, you will be able to use it to recruit local units, if any are available.

Unit Costs and Dealing With the AI

Recruitment costs are higher in XGM, and upkeep costs are very high. That means you can easily get into financial difficulties by recruiting too many units. Think carefully about  what you need, and don't recruit more units than you can make good use of. Also make sure your borders do not become over-extended. A single stack can use up the income of several cities just in upkeep so it is easy to get into a position where you can't afford to defend your own borders, let alone attack.

If all else fails, exterminate and pillage! Sometimes the only way out of a financial crisis is to conduct a scorched-earth campaign through enemy territory. When you capture a settlement, exterminate the population, destroy every building you can, and move on to the next one leaving nothing but a token garrison behind. Even if you can't hold the settlements you capture, the loot will solve your financial problems, and the damage will fatally weaken the enemy faction.

Factions controlled by the AI have less trouble with the high unit recruitment and upkeep costs because they get significant economic bonuses through unique "founding monument" buildings. These buildings are typically located in the starting capital of each faction. As a general rule, if when you go to war with another faction you should try to capture their founding monument as soon as possible.

Combat and Phalanx Warfare

Movement rates, morale levels, and kill rates have all been adjusted to produce longer more tactical battles. This has not been taken to the extremes that you will find in some mods, but still you will find that instant routs are more unusual, battles last longer, and maneuvering to flank the enemy is more important.

Unit sizes and costs have been adjusted to make ranged units and cavalry less cost effective and less all powerful on the battlefield. Still it is advisable to self limit your use of these units if you are playing infantry factions like the Romans or Greeks. Real men don't prance about on horses and throw things. :)

Units with the phalanx ability have been adjusted so that they are not entirely unbreakable. They are still very hard to beat in a frontal assault, but they are not as lethal, and it is more difficult to keep them in good order.  You can't just form your pikemen into a box and wait for the enemy to stop throwing themselves onto your spear points. Instead you should engage rapidly with your phalanx line, to pin the enemy in place, and then use other troop types to maneuver and destroy the enemy.

By the time of the game period almost all of the Hellenistic world had adopted the Macedonian style phalanx with its longer, two-handed, pikes. The Spartans were perhaps the last hold-outs, and even they adopted the Macedonian style phalanx in 220 BC. Thus all of the Hellenistic factions in XGM, even the Greek City States, employ the Macedonian style phalanx.

Still the main advantage of the Macedonian style phalanx was that required less training and cheaper equipment. Hoplites and the classic Greek phalanx did not disappear, they merely became less common as this style of fighting was increasingly reserved to wealthy elites, and self-armed mercenaries.

In XGM Hoplites are represented as heavy infantry, armed with spears, using an over-hand fighting style. They no longer have the vanilla RTW phalanx ability, but they do have a high charge bonus, high unit mass, and if you have BI they also get the shield-wall formation.

Temples and Schools

There are now significant virtues associated with all temples, and the vices associated with some temples have been toned down. So, if you have a governor in a settlement it is safe to build any temple type, and it is a good idea to build at least a second level temple to take advantage of the positive effects that this will have on your governor.

All temple types can now be upgraded by all factions, and all of the Olympian gods are now represented. In vanilla RTW it was usually a good idea to demolish existing temples in captured settlements, and to start building your own. In XGM you should always consider whether upgrading might be a better option.

Schools also have a strong positive effect on governors, so it is a good idea to build them anywhere that you expect to have a governor for long periods of time.

Loyalty

Garrison Scripts

Several important cities have garrison scripts, including Rome, Carthage, Syracuse, Rhodes, Antioch, Seleucia, Alexandria, Bactria, and Nisa. If you lay siege to one of these cities a well armed garrison will spawn at the start of the following turn. You can avoid dealing with these garrisons by attacking immediately (with catapults for example). Otherwise you should be prepared to fight a major battle.