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Hearts of Iron 4 By Blood Alone DLC review – fine flying

HoI4's new DLC By Blood Alone enhances Italy, Switzerland, and Ethopia, and adds a wacky aircraft designer - but does it make Hearts of Iron fly?

Hearts of Iron 4 By Blood Alone DLC review - author screenshot showing a battle taking place on the Italian mainland

Our Verdict

I spent some time frustrated with elements of the game, but my overall experience was one of the best I’ve had with HOI4. If you like the air war, or want to visit the 1930s as a new face, you’d be remiss to not pick up By Blood Alone.

Well, here we are. Hearts of Iron 4 is now six years old, and the latest expansion, By Blood Alone, has finally updated the long, long neglected nation of Italy. Every other major nation (and many, many other smaller nations) got some TLC over the last six years, and, now that Italy has finally been modernised (along with new focus tree updates for Switzerland and Ethiopia), it almost feels like the end of a chapter for HOI4. Everything from launch has now been updated – to the point where HOI4 is not the same game it was.

Navies, armies, supplies, spies, and, with By Blood Alone, air forces have all been made into deeper systems.

There’s a fine line in game development between additional features to the game adding depth, and those features adding bloat. By Blood Alone itself has excellent additions to the HOI4 formula – but, with everything combined, the game is veering towards that edge.

To start, let’s talk about the new focus trees; Switzerland, Ethiopia, and Italy all have new focus trees with By Blood Alone.

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First, let’s talk about everyone’s favourite neutrals: Switzerland.

The Swiss have a fairly substantial focus tree, offering political options to side with the Axis, become an independent fascist state, remain neutral (of course), or to become a sort of Central European Non-Aligned cudgel, where Switzerland gets war goals on all fascist neighbours. Funky!

The new political trees tie directly into the military for Switzerland, as they can’t actually train army units… at first, anyway. Instead, the Swiss can call up large amounts of militia units that can have their division templates modified by selected focuses, and these units can eventually be turned into regular army units if certain focuses are selected.

Hearts of Iron 4 By Blood Alone DLC review - author screenshot showing the in game regions of Switzerland and Austria

It’s certainly a significant change from any other nation I can think of, especially considering that HOI4 is, at its heart, more of a wargame than a grand strategy game, and so much of Switzerland’s tree is devoted to building up their defenses to enforce their neutrality (or not).

Switzerland almost feels like a gimmick nation, but I mean that positively. Overall, I think Switzerland is the least interesting of the three focus tree updates, but it has a lot of novel ideas that earn it a slot for a future full playthrough.

Hearts of Iron 4 By Blood Alone DLC review - author screenshot showing a world news update box for Italy's defeat by Ethiopia


Speaking of strange nations to include in a wargame, Ethiopia now has its own focus tree as well. I admit, I was uncertain how much use an Ethiopian tree would get, as they frequently get stomped out by the Italians in 1936 – but By Blood Alone has made the war more difficult for the Italians, giving the Ethiopians room to pursue a number of different political options.

The focus trees are less centralised than for the Swiss, as the Ethiopians have more flexibility in their situation, especially considering that they start the game mid-war with the Italians. Several of the focuses deal with decisions on what overall strategy to take with the war: whether to go on offensives, wait out the Italians, capitulate, or set up a government in exile to continue the fight after the front collapses in Ethiopia.

Off in the more political theory-oriented focuses, Ethiopia can opt to stick with Haile Selassie as the unaligned emperor; side with the Italians and form a joint fascist state; strike out on their own as a fascist independent state; or become communist liberators of Africa.

Hearts of Iron 4 By Blood Alone DLC review - author screenshot showing the news update for Ethiopia after a Communist revolution

What’s interesting about Ethiopia’s options here is that the unaligned and communist routes both lead to Ethiopia leading the charge to decolonize Africa – but the question of whether Ethiopia will annex the newly liberated states can vary based on the tree. Africa was a major global flashpoint after the war ended and the European powers began to slowly pull back; getting to move decolonization earlier in the timeline during a period of larger conflict is fascinating, in my opinion.

Hearts of Iron 4 By Blood Alone DLC review - author screenshot showing a battle taking place on the Italian mainland


And lastly, of course, we have Italy. Italy, like Ethiopia, has focuses centred on the war, but, interestingly, if you want to pursue a non-fascist option, you’re encouraged to commit to losing the war, as the loss of the war will allow for more political opponents to join an opposition party.

I appreciate the overall desire of this DLC to try to be realistic with its ahistorical options, as previous DLCs have been somewhat more loose with those focuses that diverge from real-world history. Italy’s options are, of course, to remain fascist, become fascist in a less ‘Duce’ direction, or to go communist or democratic-socialist.

These trees all offer quite a bit to do, and they really focus on Africa, a largely irrelevant continent prior to By Blood Alone. Italian interest in Africa can vary from wanting to expand colonial possessions to a more radical approach, as a communist Italy can support decolonization efforts through war, just as Ethiopia can.

Hearts of Iron 4 By Blood Alone DLC review - author screenshot showing the new Balance of Power system for Italy

Balance of Power

One new part of politics I haven’t mentioned until now is the Balance of Power system, a new scale unique to Switzerland, Ethiopia, and Italy. In short, what this system does is measure governmental power and influence from the main governmental factions.

Some focuses and decisions will tip the balance more to one side, and, as the balance becomes more weighted towards that side, the country gets increasingly powerful bonuses. For example, as communist Italy, the two factions are the communists and the socialists. Taking actions that benefit the communists lead to growing bonuses in manpower and popularity of communism, while developing the socialist side will grant easier diplomatic relations with other states.

All the political trees I’ve mentioned (as far as I can tell, at least) have a factional system at some point, and, while it isn’t a very large part of the game, it is a neat little feature that adds more colour to your country’s governing style. My only gripe with it is that it’s a system that would make every playable country feel more alive – but it’s only available for the three newly expanded countries in By Blood Alone.

Hearts of Iron 4 By Blood Alone DLC review - author screenshot showing the in game aircraft designer

Fly Boys

And of course, I would be remiss if I didn’t mention the new aviation system. Perhaps calling it a new system is incorrect, as the core of the air war hasn’t changed. The combat aircraft can, however, now be modified just as much as ships and tanks can.

Weapons, modules, and even the amount of engines on the plane can be customised to best fit the fighting needs of your country, and you can get real wacky with it. By that I mean you can stick four engines, four sets of guns, and four turrets on a medium airframe for an absurd flying fortress that exists purely to punish any enemy planes for existing near it.

If you have experience with modifying ships or tanks from the previous expansions, you’ll be familiar with the way the aircraft customisation works, though modifications are much cheaper here than for tanks or ships, as it’s much easier to throw together new plane models than new tank or ship models.

The customisation system really sucked me in, and I spent a great deal of time messing around with it and creating real Frankenstein-type aerial abominations, though I have some issues with it as well.

Hearts of Iron 4 By Blood Alone DLC review - author screenshot showing an air battle over Britain

For one, at least in the review build I played, the Ground Attack and Naval Attack fields were bugged, always reading as 0 and 1 respectively, even if the true value was different. This was frustrating, as I had to go in and manually count up the values of each module on a plane to determine what the actual values of the plane were.

Additionally, the game will classify planes as a certain class, and it’s difficult to determine what differentiates a naval bomber from a heavy fighter from a close air support fighter when there isn’t any tooltip telling you.

Overall, this isn’t such a large problem, but it means that planes determined as a different class won’t be used to reinforce air wings of a certain class automatically, so you have to spend time manually picking through plane types and assigning them.

Hearts of Iron 4 By Blood Alone DLC review - author screenshot showing an air war over Italy

This frustration is compounded by the fact that the new air UI is a bit labyrinthine. It took me a bit of time to figure out how to set up air groups, how to select specific air wings, how to set up new air wings or modify existing air wings, etc. This is a problem that already exists in the naval side, but it’s worse with the air component because most nations that invest in their air force can quickly amass thousands of planes, and sometimes they’ll need individual attention.

My complaints aside, my time with By Blood Alone was just plain fun. I mentioned earlier that there’s a fine line between having a lot of good features and mechanics in a game, and having it be bloated – and, while I feel By Blood Alone pushes the game towards that line, we’re not quite there yet.

This review was updated on September 28, to include Paradox’s Launch Trailer for By Blood Alone. The review text was not amended.