This is the second in a series of reviews of Paradox’s empire management games. See the first review here:
Europa Universalis II: A Tale of Two Europas

After Europa Universalis II, Paradox Interactive stuck with what they had proven that they do well, and started work on more empire management games. WWII is apparently Johan Anderson’s favorite historical period, which became the subject of Paradox’s third title, with Hearts of Iron covering the years 1936 to 1948. It is generally regarded as using the same ‘engine’ as EU II, but very little actual code survived the transition. It was released for Windows and Mac OS X in 2002, and did not have any expansions, but an version updated to the last patch (HoI Platinum) was released in 2004 with more events, re-done AI, a new scenario, and a revised manual. I’ve only played the Platinum version, so this review will only reference it.

At first look, HoI is very much the same thing as EU II: it is a pauseable real-time game where you take control of a country (any country), and manage its military, diplomatic, and economic development. (In fact, other than the real-time part, that’s what I mean by ’empire management game’.) It has an area-based map of the world, where military units can move about and fight in a battle that can take some time, but the only outside decision in the combat, once joined, is whether to retreat from a losing fight. So… change the date, put in tanks for cavalry and call it a day?

However, past the most superficial overview, there are major differences: Religion does not appear in the game. Since the scope of the game has contracted from four centuries to twelve years, hours tick by, instead of days (and the day/night cycle sweeps across the world, and can be seen in the minimap, and affects combat). Diplomacy is greatly simplified, and governments now have internal ministers that can provide various bonuses.


The trade and money system of the EU series is absent here, replaced by a resource system more common to various conquest-style games. The general resources are industrial capacity, coal, steel, oil, rubber and supplies.

Any sort of production (including research) consumes industrial capacity, which is the pool of industry available in all of your controlled provinces. In addition to the normal production of new units, it is used to generate consumer goods (if you don’t satisfy the demand the civilian population gets restless), and supplies, which exist in a pool which is consumed by military units (at a constant rate, higher on the move and in combat, and then there are surcharges for reinforcing a unit).

Steel, coal, oil and rubber come from specific provinces on the world map, and if you don’t have all of them, you need to trade what you do have for what you need. Instead of the wide variety of commodities generating money through trade as in EU, the economic system focuses on just these few. Trading with a foreign power is accomplished largely by making an offer in kind on the world market. If no one wants it, it’ll be marked in red, and you can sweeten the pot by offering more of what you have per unit of what you’re trading for.

Rubber is by far the most uncommon commodity, but this is the era where artificial rubber was starting to be produced, so you will automatically turn oil into rubber if you have one and not the other (at a fairly poor rate, but there is technology that improves this). Similarly, coal is the most abundant resource, and some will automatically be turned into oil if your oil stocks run out.

Shipping is also important, and if you have overseas territories that produce resources, convoys will have to be set up to ship them home so they can be used. These do not appear on the map, but are subject to being intercepted by enemy ships (that are on the map) during wartime.

Finally, there are improvements that can be made to the provinces themselves. Industrial capacity can be built, AA batteries can be built to defend against air attacks, fortifications can be build to defend against land or amphibious attacks, and the infrastructure can be improved to both increase resource output and increase movement speed in the province, but all these take some of the existing industrial capacity in the province out of action.

Politics and War

Instead of every country working out alliances out of practicality or for protection, HoI has a tripartite power struggle. Each country falls within a triangular space of political ideology with the points being democracy, socialism or fascism. There is one alliance for each of these ideologies, with the Axis permanently led by Germany and the Allies permanently led by Britain. (The Soviet Union is the leader of the Comintern, but can dissolve that alliance to join either the Axis or the Allies.)

Peace settlements are also much simpler than in EU. You can annex a country, or you can make it a satellite nation (both requiring that you hold significant parts of the victim), or you can return to the statis quo antebellum; there is no negotiating a peace in return for a couple of provinces, it’s all or nothing, unless you have specific territorial demands on a country, in which case you can diplomatically demand the territory, or go to war over it, in which case the other country can surrender the territory.

You can spend diplomatic influence with other nations to try to influence their governments towards your political ideology. A country that shares your ideology can then join your ideological alliance. In general, the game tries to enforce a tri- or bipartite power structure, as most wars will force one or both parties into the alliances, if they aren’t already in one.

However, the main democratic nations try to keep out of wars at the beginning. They have an extra rating of what percentage of the population supports going to war. This starts off low, and generally goes up about 1% a month. Aggressive actions from Fascist or Communist nations will tend to speed this up (though fighting within a faction will slow it down). Once at 100%, a declaration of war, or joining the already at-war Allies usually follows (this apparently will often target Germany, so playing a peaceful Germany is difficult to do).

To counterbalance the simplified external relations of the country, the internal power structure is more detailed. There are eight ministers that can be appointed out of a pool of historically appropriate people (in some cases the entire pool is one person…). In addition, there are two are special cases: the head of state (who can only be ousted by a coup or election) who determines the general ideological leaning of the nation, and the head of government, which is effectively the player, and determines the AI behavior of a non-player country. Each minister has a personality which provides bonuses or penalties to things like construction efficiency or dissent.

That last, dissent, is effectively the stability replacement of HoI. Dissent causes loss of production, guerrilla armies to crop up, and erodes the loyalty of the ministers, which is one of the few hidden statistics in the game. Ministers with very low loyalty can end up deliberately sabotaging government projects, but this is hard to see.


Unlike in EU, military units are indeed units in this game. Instead of recruiting 1000 infantry which is slowly attritioned away and eventually disbanded or supplemented with fresh recruits, you organize a division (or air wing, or ship), which exists as a discrete organization. Every unit has a strength and a organization rating. The latter is effectively morale, and the usefulness of a unit is effectively its applicable combat statistic times strength times organization. A unit at zero organization is making no contribution to the battle (though it is continuing to absorb damage), and when all units in a force are at zero organization, it must retreat.

Organization slowly comes back to its maximum when the unit is sitting still and doing nothing. Strength can only be replenished by user intervention, and reinforcing a unit will drop its organization value while the new troops are properly integrated into the formation, forcing the unit to stop and reorganize for a while (at least, if there was any appreciable amount of strength to replace). Moving around in bad weather/climate can also reduce organization, making attacks in extreme climates harder to manage.

When moving into a province that currently has enemy units, a little clock dialog appears, where you set exactly when your units show up. This allows coordinated attacks from different provinces (which provides a bonus), air attacks to go in right before hand, infantry to engage the enemy right before the tanks show up and try to break through, etc.

Unlike the three basic troop types of EU II, there are a bunch of possibilities in HoI. Just in ground divisions, there is regular infantry, motorized and mechanized divisions, armor, mountain troops, paratroopers, marines and militia. All of these have different abilities, and most can have brigades (anti-armor, anti-air, artillery, or engineers) attached to them (as a permanent part of the unit) to enhance the normal stats. Units can be grouped together into larger structures as needed, and leaders can be assigned to them. These are rated by skill, which improves performance in combat, and rank, which determines how many units they can command without penalty. However, managing the units, and their parent organizations is one of the pain points of the interface, as most of the information you want isn’t present when managing the units. You can (for instance) separate a weakened unit from a force so it can stay behind and rest, but the display to do it only displays the unit names, so you need to work out which ones need to be culled first, and then remember their names.

In keeping with the mobile warfare, and continuous fronts, of twentieth century warfare, there is no need to besiege a province. It passes to the control of the invading country as soon as the enemy is driven out, and the fortifications that can be built in a province instead directly help the defending force in combat. Supply is very important in HoI, so a chain of provinces leading back to the home country is needed, or the cut-off forces will slowly become less and less combat ready (if invading overseas, a supply convoy must be set up to supply units, in the opposite pattern as convoying resources from overseas home).


WWII has sometimes been called ‘the wizard’s war’, with technological progress driving many of the turns the war took. This shows up in a number of WWII games, from the equipment upgrades of Panzer General, to the research projects of Axis and Allies.

HoI has one of the most extensive technology systems there is for a WWII game. There are fourteen different subject areas, each with theoretical and applied projects to research. The theoretical ones need to be researched in order to get the next batch of applied projects, but have no prerequisites other than the previous theoretical project. The applied projects are all grouped under various theoretical projects, and often have other prerequisites, either from within the subject area, or from another subject area.

The effects of the practical applications vary quite a bit. There are Land, Air, and Sea Doctrine subjects that mostly increase the maximum organization rating of the appropriate units, and therefore make them more effective in combat. Electronics research is often needed in other fields, and includes advances that make surprise more likely (when attacking) or less likely (when defending), mostly to do with encryption and radar technologies, and also includes the early computers developed in the period as an aid to further research. Rocket and Nuclear research needs a lot of work to pay off, but eventually allows new unit types. Infantry and Artillery research enhance the abilities of existing units. Armor, Aircraft and Naval research all allow new vehicle types, and units must either be upgraded to them or built fresh.

This last combines with several of the unit types, where they are assigned a particular vehicle type, and if you want to re-equip your armor division from Panzer IIs to Panzer IVs, you have to select it, and re-equip it, and it will then spend time off the map in the industry production queue. This only applies to tanks and planes however; with naval units there are upgrades to their basic stats that require you to refit the ship in the production queue, but you do not change the actual class of ship.


As usual, Paradox has provided a very good electronic time machine with HoI. It does concentrate on trying to bring forward many of the most important aspects of the period, the ideologies/politics, rapid evolution of technology, and a sweeping total global war.

HoI uses an event system similar to EU II‘s, scripting in major events such as the Spanish Civil War, and Lend-Lease shipments. There are several of these dealing with the start of WWII, which has the effect of scripting parts of the setup of the conflict—which certainly helps keep the AI on-script. In general though, there is much less use of events than in EU II.

For all the details about vehicle types, they don’t feel well served. All the interdependencies tend to be overly detailed (taking several otherwise useless steps to get a new model), and very logical and linear. Logical and linear in ways that don’t follow how actual vehicle development worked. Most egregious is tanks, where you must research light tanks, and then improved light tanks, and then move on to medium tanks. The game completely ignores that light, medium and heavy tanks all had different roles, and were generally developed in parallel. Concepts like the infantry tank (slow, heavily armored tanks with light guns) are effectively ignored to fit into the straitjacket of the progression. On the other hand, the development of things like tank destroyers is presented in a slightly parallel track, and just add bonuses to units, abstractly representing the integration of these specialist vehicles into the main organization.

Important themes like the strategic bombing campaigns, the struggle over shipping, the evolution of equipment and doctrine are all given attention, and handled well. Subjects like combined arms don’t work out as well (partially because things like paratroops are hard to use), but effort was put into it, and the ideas are sound.


HoI is a complicated game, but the AI generally seems to know how to play it well, and what it lacks in smarts is made up by the ability to handle several subjects in detail at once.

Much of the point of ground combat is preserving supply lines, so units do not take lack of supply penalties, and can rest to regain organization when needed. The AI understands this, and generally maintains fronts well, which means that fronts with two AI players facing off tend to devolve into limited shoving matches, with the occasional breakthrough that is usually cut off, but more often turning into a staring contest between high stacks of units in rough terrain.

In naval affairs, the AI seems to have more trouble, with fleets in the Pacific in particular tending to get cut off far from home and supply, and vulnerable to defeat in detail. However, it does understand the convoy system well, and will effectively disrupt shipping if critical areas are not protected.


I have found that HoI is my least favorite of the initial Paradox empire management games. Part of this is because I find it overly fiddly, and concentrates too much on lower-level items that clash with what I expect to see in a grand-strategy title. Also, there are some real problems with the shift from the exploration and limited war model of EU II to the total war presented in HoI. You can end up needing to coordinate military operations in widely separated areas at the same time, and that is never a good fit with a real-time title, pauseable or not.

However, I think the real problem lies elsewhere. One of the things I enjoy about Paradox’s games is a certain sense of discovery. I like history, and I know something about any period they have, or will, tackle. However, these games always show me something new, there’s a lot of world out there, and just scrolling around the map will show you something that you hadn’t heard of. On the other hand, the world of 1936-48 is much more familiar to me, so I am not really finding new facets of history in it. Furthermore, I have a lot more experience with WWII from a game perspective, so I am also bringing more concrete expectations to it.

There are also some definite poor fits scale-wise. Using divisions as the basic unit of armies, which most major countries fielded well over a hundred of, and then (in Europe) fitting all these divisions (plus air units) into a front that’s maybe ten provinces wide causes all sorts of pain in trying to manage it all, that the UI just has no hope of dealing with.

All that said, it is a good game, and in representing many of the primary concerns of the period, shows a good amount of flexibility of approach from Paradox. For anyone who plays it, I recommend getting familiar with the game, and then looking at the Undocumented Features List thread on Paradox’s forum.

There’s some very good info in there, once you have some context for it. Item numbers 9, 27 and 7 are helpful to get around some of the problems with the UI.