Hearts of Iron IV turns 10: a retrospective on the decade that redefined grand strategy

On June 6, 2016, Paradox Development Studio launched Hearts of Iron IV. At the time, nobody bet on a success exceeding three years — WW2 grand strategy was niche, initial sales were modest, and the competition from Company of Heroes 2 or community HOI games remained strong. Ten years later, HOI4 is Paradox’s most-played game, with over 30 million cumulative players by Steam’s latest estimates. A look back at a decade that rewrote the rules of PC grand strategy.

TL;DR:

• 2016-2017: promising but imperfect launch, the community fixes what Paradox overlooked
• 2018-2020: golden age of DLCs (Man the Guns, La Résistance) + mod explosion (Kaiserreich, TNO, Millennium Dawn)
• 2021-2023: No Step Back, By Blood Alone, Arms Against Tyranny — Paradox refines the formula at the cost of a heavy DLC stack
• 2024-2026: Paradox Tinto takes over, modernizes the UI, officially collaborates with modders
• The future: Thunder at our Gates (Australia/Thailand/Indonesia), naval overhaul, 10th anniversary under the banner of click reduction

Table of contents

• 2016-2017: imperfect launch, patient community
• 2018-2020: golden age of DLCs, mods validate the game
• 2021-2023: mature formula, but the DLC gets heavy
• 2024-2026: Paradox Tinto, modernization, modder collab
• The 5 mods that redefined HOI4
• What’s coming: Thunder at our Gates and the naval overhaul
• Verdict: where does HOI4 stand 10 years in?

2016-2017: imperfect launch, patient community

June 2016. HOI4 hits Steam with a clear promise: simplify HOI3’s heavy formula without betraying it. The bet is partially met. The UI is readable, equipment production abstract but elegant, combat system more snappy. But the game suffers at launch:

• National focus trees limited to the 7 major powers (Germany, USSR, USA, UK, France, Italy, Japan)
• Naive AI struggling to run coherent campaigns past 1941
• Naval and air mechanics anemic compared to land
• Little non-European content — the Pacific is playable but empty

Fortunately, the modding community jumps on the game immediately. Kaiserreich, ported from Darkest Hour, drops in late 2016 and offers an uchronia where Germany won WWI. It’s the first thunderclap — a mod more ambitious than the base game.

DLCs roll out at measured pace: Together for Victory (2016, Commonwealth), Death or Dishonor (2017, Central Europe). They add focus trees where the base game cruelly lacked.

2018-2020: golden age of DLCs, mods validate the game

Starting in 2018, Paradox finds its rhythm. Waking the Tiger (2018) reworks China and Japan with unprecedented depth. Man the Guns (2019) modernizes the navy. La Résistance (2020) introduces spies, resistance networks, and coups — a major gameplay pivot. It’s the first true “mechanics” DLC, elevating HOI4 to full-fledged grand strategy status.

On the mod side, 2018-2020 sees the explosion of The New Order: Last Days of Europe (TNO), a dystopian uchronia where the Reich won by 1962. Dark tone, dense narratives, integrated visual novel — TNO becomes the most-downloaded mod in the entire grand strategy category on Steam Workshop.

Millennium Dawn opens another front: playing HOI4 in 2000 (or 2017, or 2024 depending on version), in a contemporary world. It’s the mod that convinces non-WW2 fans to buy HOI4.

2021-2023: mature formula, but the DLC gets heavy

No Step Back (2021) is arguably HOI4’s best DLC. Full USSR rework, High Command Balance of Power system, new equipment divisions — everything is there. Followed by By Blood Alone (2022, Italy/Switzerland/Ethiopia), Arms Against Tyranny (2023, Scandinavia).

But the model starts to weigh. Players must shell out nearly $300 to own every DLC. New entrants are intimidated. The community splits between “you need them all” and “Paradox is milking us.” The debate on Paradox’s DLC model (which we analyzed in our article on 25 years of Paradox DLCs) grows tense.

2024-2026: Paradox Tinto, modernization, modder collab

Late 2023, Paradox restructures. Paradox Development Studio (PDS) refocuses on Europa Universalis V in development, and Paradox Tinto (the Imperator: Rome 2.0 team) inherits HOI4 support. The change is immediately felt:

• Trial of Allegiance (2024): South America rework, excellently received
• Götterdämmerung (2024): major expansion on the Reich’s end, dark narratives
• Graveyard of Empires (2025): Afghanistan, Iran, Middle East — a long-forgotten zone
• Peace for Our Time (April 2026): Czechoslovakia Focus Pack co-designed with official modders — a first

In parallel, free 2026 updates focus on “Click Reduction Technologies” — UI modernization and reduction of click-intensive micro-management, aligned with EU5 Rossbach’s Unit Templates. Paradox Tinto is converging the UX of all its games.

The 5 mods that redefined HOI4

Impossible to talk HOI4 without mentioning its mod ecosystem, the richest in the entire grand strategy category.

1. Kaiserreich — “Germany won WWI” uchronia. Over 150 focus trees, dense narratives, considered a second base game by many.
2. The New Order: Last Days of Europe — 1962 dystopia, a crumbling victorious Reich. Unique visual narrative, 20 playable nations with deep focus trees.
3. Millennium Dawn — contemporary world. Lets you play the late Cold War, the 2010s, even 2024 depending on the branch.
4. Old World Blues — Fallout crossover. Alternate-history nuclear post-apo, new radioactive mechanics, retrofuturistic aesthetic.
5. Road to 56 — base game extension. Adds dozens of focus trees for small nations overlooked by Paradox.

These 5 mods account for, per latest Steam Workshop data, over 60% of HOI4 playtime outside vanilla scenarios. It’s an ecosystem without equivalent on PC.

What’s coming: Thunder at our Gates and the naval overhaul

Paradox Tinto confirmed in its April 2026 State of the Game:

• Thunder at our Gates (Q3 2026): new Country Pack with focus trees for Australia, Thailand, and Indonesia. The long-ignored Southeast Pacific finally covered.
• Naval overhaul: currently in open beta, full rebalance of submarines (deemed “too easily detected”), carriers, and escorts. Ships with patch 1.16 scheduled for summer.
• Performance and AI: ongoing fixes, priority on late-game campaigns (1942-1948) where lags pile up.
• 10th anniversary celebrations: kept secret until the big day (June 6). Rumors of free skins, a Steam event, and possibly a sale on all DLCs.

Verdict: where does HOI4 stand 10 years in?

HOI4 in 2026 is a more complete, more refined, and more alive game than at launch. The original critiques — weak AI, anemic navy, missing non-European content — have been largely addressed by 10 years of patches and DLCs. The new critiques — cumulative DLC price, growing complexity — are the flip side of a formula that works.

For a new player in 2026, the right entry point is:

1. Base game + Peace for Our Time ($5.99 — great intro)
2. Then No Step Back or La Résistance (based on East/West preference)
3. Add a mod (Kaiserreich for a gentle start, TNO for narrative)

For the veteran, April-June 2026 is an ideal moment to come back: Peace for Our Time just dropped, Thunder at our Gates approaches, naval patches incoming. And for the full retrospective on winning strategies, see also our HOI4 mods guide 2026.

10 years in. And the best may still be ahead.