Hearts of Iron IV

Every one of Paradox Development Studio's strategy games scratches a different itch. Crusader Kings II is a personable and lively family tree simulator. Europa Universalis IV is about diplomacy and new world conquest. Stellaris is about seeking out new life and new civilisations. The most recent addition to the family of games built with the Clausewitz Engine is Hearts of Iron IV, and this one is all about the simulation of war, and juggling the micro and the macro.

If the recently released Stellaris is the most accessible Paradox game to date, then we reckon HOI4 might well be one of the hardest to penetrate, at least for newcomers. The studio has crafted a complex sandbox simulation, packed with a dizzying array of options for armchair generals to pick their way through. Compared to the studio's century spanning titles that we've been playing of late, this is much more focused, with all the action concentrated around the decade that housed WW2.

There's two starting points, and each offers a different experience. Begin your campaign in 1936 and you have time to prepare for the coming storm. And come it will. There's no getting away from the inevitable conflict, but you can choose exactly how you want to setup in advance of it. There's options aplenty, from politically-charged decisions that define the government of your country, to the choices you make regarding military appointments and the infrastructure of your industry.

The first part of the game is gently paced, and you'll click through menus, researching this, building that, and generally having a jolly time as you go about your business. There's a fair amount of watching timers run down, but there's so many different buttons to press, and such varied directions to take your growing military force, that the wait between decisions is eased by the fact nearly all of them are interesting. There's a different pace to peacetime, to the extent that it feels almost like a different game.

You can play as any country, but the research options (and there's a lot of them) are geared around the major players in the war. You must decide which way to sculpt your wartime nation via several mutually exclusive tech trees that need climbing, and you need to research a different national focuses every couple of months. Slowly over time you mould your country as if out of digital clay, and come the end you've a military machine that mirrors your past decisions (for better or worse).

One of the things that impressed most in HOI4 is how it facilitates emergent stories, allowing you to bend history to your will, at least within the confines of the scenario. Some of your choices can be extremely impactful. For example, when we turned Britain into a communist state, our French neighbours deserted us, as did our Commonwealth allies, but we were kept out of the war until 1941, until the Japanese made eyes at Hong Kong and declared war. At this point things started to fall into place, and eventually we were left with fairly traditional battle lines stretching across Europe and the Middle East, with a second front in China. Similar outcome, but the journey there was very different. Despite being extremely focused in some respects, there's still room to manoeuvre your way through the war and create alternate histories.

The second starting point is 1939, with the world sitting on the cusp of conflict. Here there's much less emphasis on the research side of things (you still have to make your choices and advance through the tech trees, but instead of being a primary focus, these research projects merely tick away in the background). There's still opportunity for divergent timelines, and your own successes and failures on the battlefield, as well as those of the AI-controlled states, will certainly send you on a different path to the one trodden in history books, but unless you're deeply knowledgeable about the history of the period you might not notice some of the more slight deviations.

If picking research and building factories is the macro, then moving divisions around the world map is the micro. There's a combat system whereby an army is given a battle plan with an objective, a direction of attack, and defensive lines to fall back on if things don't go as well as planned. There's obviously stats clashing underneath the surface (and you can tinker with the composition of your divisions quite a bit during the planning stage), but it isn't always clear why a battle is going one way or another, or why some of them take as long as they do to play out. The AI also makes the occasional baffling decision, but then again, don't we all.

On top of moving your divisions around the various theatres of war, you can also set your naval units to patrol the seas, protect convoys, or seek out and destroy enemy vessels. Aircraft carriers carry fighters and bombers out into the oceans, and you've also got land-based airfields that you can stock up with various types of planes, and assign them missions that play to their strengths. If you're commanding one of the super powers, there's an awful lot to take in, so much so that it can be overwhelming while you find your feet.

In fact, Hearts of Iron IV doesn't make things easy for newcomers; the tutorial is very vague and hardly scratches the surface in terms of telling you your options. There's so many interlocking systems that rely on each other, and it's easy to neglect one area if you don't know what you're doing, which in turn can affect other parts of your war effort. There's values assigned to various actions, but the game does a bad job of telling you what half of them actually mean, and while understanding gradually arrives in time, like the fog of war lifting in an RTS, the lack of guidance regarding some of the more intricate systems just isn't good enough.

While we're rolling out our gripes, there's a couple of things missing that would've made for a more complete experience. You can decrypt enemy transmissions and the like, but there's no espionage, something that would have made the 1936-39 part of the game much more intriguing. Similarly, after 1939, there's no option to support conquered countries, for example sending aid to the likes of the French Resistance.

The biggest omission, however, is the absence of meaningful diplomacy. You can ask your allies for military access and so on, but there's no option to coordinate attacks, and this is a big miss. You do your thing, your allies do theirs, and hopefully your efforts coalesce into victory, but you can't work together to hit your enemy where it hurts the most. Obviously this issue is non-existent in the online multiplayer part of the game, where plotting and scheming is part of the fun, but we wanted more and better tactical cooperation between states in single-player.

Looking beyond what's missing or hidden away, it's clear that Hearts of Iron IV is an expansive and detailed war simulation. For armchair generals looking to manage every facet of the war machine, there's enough depth here to keep you busy for months and months. There's a lot going on, and especially during the early game, a lot of waiting while timers tick down, but even during the more lethargic moments there's a fairly constant stream of interesting decisions to make, which keeps the boredom at arm's length (for the most part).

The pacing of the campaign might swing from sluggish to frantic, but it also boasts a huge range of options and some intricately woven systems. It's not perfect by any means, but for military strategists who aren't scared off by the density of the simulation, it's a war worth waging.