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Hearts of Iron 4 Trial of Allegiance DLC review - gone South

The latest HOI4 DLC pack flies to South America, adding new focus trees and options for Brazil, Chile, and Argentina - but is it any good?

Hearts of Iron 4 DLC Trial of Allegiance review - author screenshot from the DLC showing South American soldier 3D models firing submachine guns in combat in game.

Our Verdict

Hearts of Iron 4: Trial of Allegiance is a decent DLC with some bright spots, but it's marred by lacking both new mechanics, and sufficient variety in its new military focuses. The new focus trees have their moments, but much more could have been done to make them unique. It’s not a must-have addition, but if you want to bring the war to South America it's a solid pickup.

Reasons to buy
  • Adds more depth and options to an underplayed WW2 region
  • All three main nations are genuinely fun to play
  • Some cracking new ahistorical options
Reasons to avoid
  • New military focuses are disappointingly similar
  • Costs the same as other DLCs, but adds no new mechanics
  • Some minor bugs interfere with focuses and decisions

South America is often an under-used region in Paradox titles, but new Hearts of Iron 4 DLC Trial of Allegiance aims to remedy this, sewing the continent into its already giant WW2 blanket. Historically, the fighting in the region was extremely limited – but this expansion brings in full focus trees for some key nations on the continent, with both historical and ahistorical options for us to dig into. How does it stack up against previous HOI4 expansions? Read on to find out.

First things first: unlike many of the prior Hearts of Iron 4 DLC packs, Trial of Allegiance expands upon focus trees but doesn’t add any new mechanics to the game. Three main nations get shiny new, complete trees: Brazil, Argentina & Chile. In addition, smaller but still detailed focus trees have been added for Paraguay and Uruguay.

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Outside of WW2 games, South America was quiet during the real World War 2 – but some significant historical events did take place there, such as Axis intelligence actions in the region (Operation Bolivar) and key supportive actions, such as Brazil joining the allies and sending troops to Europe.

Happily, the DLC touches upon all these. All things considered, there’s a pleasing spread of ahistorical content to enjoy too, and I found both campaign types (starting in 1936 or 1939) to be very engaging for each nation.

Hearts of Iron 4 DLC Trial of Allegiance review - author screenshot from the DLC showing the new Chile Focus tree

Chile

Each of the freshly updated main factions will face initial challenges in the run-up to war. First up is Chile, which is in the awkward position of needing to deal with a potential coup in the offing, as well as unrest from the indigenous Mapuche populace.

The player will get the tools to deal with these problems as they advance through the focus tree, but speed is of the essence in order to avoid more strife arising. Later in the game, there are plenty of interesting optional paths to go for, whether it be striking towards Peru or igniting a war with Argentina over the Patagonia region.

Hearts of Iron 4 DLC Trial of Allegiance review - author screenshot from the DLC showing the leader and government panel for Chile

On reflection, I think Chile was my favourite new addition, as it can make some incredibly strong divisions – based on infantry and artillery – with which to overwhelm its opponents. This is tempered by the challenge of a small population with limited recruitment – so you need to be very careful with your strategic choices.

Hearts of Iron 4 DLC Trial of Allegiance review - author screenshot from the DLC showing the new Argentina Focus Tree

Argentina

Next up is Argentina – which was the South American nation historically closest to the Axis powers, so naturally its focus tree can reflect this if you so choose. Argentina is in a similar position to the other regional powers, in that it has a pile of internal issues to solve before it can think about joining any conflict.

However, it has plenty of tools at its disposal to adequately resolve any situations that arise as you progress. I found that the focus trees for Argentina offered a good balance of warfare and economic buffs across each ideology type, although I do feel the fascist and democratic trees were stronger than the communist options available.

Hearts of Iron 4 DLC Trial of Allegiance review - author screenshot from the DLC showing Brazilian troops massing on the Chilean border

Brazil

Starting off in a state of national upheaval is a bit of a trend in this DLC. Brazil also kicks off the game with an unstable government and a weak economy, still recovering from the Wall Street Crash years after it occurred. The player must decide whether to end the state of emergency it’s in at the outset, or exploit it to embrace a new political system.

Other threats, such as the Cangaço banditry and separatist sentiments, will also demand your attention – and dealing with these starting issues is paramount in order to bring Brazil onto the world stage.

Hearts of Iron 4 DLC Trial of Allegiance review - author screenshot from the DLC showing South America on the country select map, zoomed in close.

In my playthroughs, I found Brazil fun to command – partially because, of all the DLC’s main nations, it has the most potential to properly influence the course of the war. I particularly enjoyed the democratic path, which allowed me to usher in a rather spicy alternative history: uniting South America under the banner of the United States of South America.

Besides the aforementioned three big continental players, there are also new (but much smaller) focus trees for Paraguay and Uruguay. These weren’t as detailed, but they’re still a welcome addition and help to flesh out the region further.

Hearts of Iron 4 DLC Trial of Allegiance review - author screenshot from the DLC showing various forces vying for control of central america and the Panama canal.

Weak on warfare

Unfortunately, Hearts of Iron 4: Trial of Allegiance also has some serious disappointments in the mix. The political parts of the new focus trees for the big three nations are good additions – but the military parts were distinctly underwhelming by comparison.

For a game predicated around warfare, you’d expect the warfare trees for each nation to be, if not unique, then at least meaningfully different – but that’s not the case here. The army, air force, and navy components in the Brazil, Argentina, and Chile focus trees are mostly the same, with only minor differences here and there – which is an extreme let-down.

Hearts of Iron 4 DLC Trial of Allegiance review - author screenshot from the DLC showing the leader and government panel for Chile

The DLC’s leading countries do get powerful new bonuses to ensure that whichever nation you pick can more than hold its own, but I feel there should have been more unique military options available for each nation.

I ran into some troubling bugs as well – a couple of focuses didn’t work properly, and I ran into some decisions that I couldn’t take, even though I had the prerequisites. These were minor problems overall and it didn’t detract from my experience too much, but it’s worth bearing in mind, especially alongside the shortcomings in the military focuses.

Hearts of Iron 4 DLC Trial of Allegiance review - author screenshot from the DLC showing aircraft units moving south over the English channel during a game.

Finally, at a price of $14.99 (£12.79), Hearts of Iron 4: Trial of Allegiance is a little too expensive, in my opinion. Sure, there’s some intriguing content in this DLC’s new focus trees, but there’s a lot of aggravating repetition too – and, in stark contrast to other DLC packs at the same price point, we don’t get any new mechanics.

Folks particularly interested South America (and completionists in search of HOI4 achievements, of course) shouldn’t miss this one – but, for most others, it’s going to fall far short of ‘essential’.

For more HOI4 coverage, check out our guides to the best Hearts of Iron 4 mods to try, and our complete list of Hearts of Iron 4 console commands to mess about with your playthroughs.

Alternatively, check out our broader guides to the best grand strategy games and best 4X games you can play on PC right now.

Meanwhile, we’ll all keep on praying for Hearts of Iron 5.