Hearts of Iron 4 first look: a slick return for the veteran World War 2 strategy series

Back to World War 2 we go, for some intense, detailed, slow-burn strategy.

Back to World War 2 we go, for some intense, detailed, slow-burn strategy. The Hearts of Iron series has typically been a daunting prospect because, well, look at it, but the fourth entry will be different. A buff 3.0 edition of the Clauswitz engine powers the sandbox. The oppressive grey backgrounds of old have been replaced by muted colours, and an adaptive interface that outlines and shades countries depending on your zoom level. A night/day sine wave washes slowly across the map, separating the brushed iron surface into sunlit and blue moonlit zones. The units are no longer featureless rectangles, but tiny models that can be guided around with multi-phase battle plans. These are sculpted with stretched, curving arrows and broken lines, depicting troop movements and battle lines respectively. I'm surprised Paradox haven't put out any screenshots yet; this is a very inviting strategy game.

There's design reasoning behind Hearts of Iron's new-found aesthetic flair. The day-night cycle may seem like a bit of visual frippery, but you have different attack options if you launch attacks in the dim cobalt night zones. "Some nations have bombing aircraft set up for night attacks, some for day," explains designer, Dan Lind. "There are different routes you can research. Some nations will focus on specific tactics during night, like the Japanese have these neat attack special attacks they can select. It's stuff that any nation can do, but some of them fit more into where they are in the world. I can wait and launch my plan at dawn, if I want, or do it at night."

Sketching out offensives with arrows adds a tactile element to planning, but can also boost the strength of an attack. Offensives are more powerful if they follow lines that have been in place for some time ahead of execution. That encourages decisive plotting, and plays into the clever new espionage system - spies can uncover those arrows and adapt to incoming attacks accordingly. "You can steal plans, and you can also draw helpful plans for allies. If you're Britain, for example, and you're doing the D-Day landings, you'll have a lot of allies and you can actually draw plans for them as well."

The espionage system should also work nicely in multiplayer. Hearts of Iron multiplayer sessions support up to 32 players, and there will be a co-operative option that'll let friends take charge of different aspects of a single nation's operations.

Just because you've drawn up a plan doesn't mean it'll execute flawlessly. Terrain - visible at high zoom levels - will have a significant affect on troop movement, which is further complicated by the passing seasons. A wet August can reduce bogs to deadly marshland, and winter in Russia will be typically punishing. The troops you're pushing around will, of course, represent historically accurate World War 2 units, but the top of the technology tree will extend beyond the reach of history. The war ended for Germany before they could roll out their standardised Entwicklung series of tanks, but if you survive long enough, you can research and deploy them as Germany might have. You can breathe life into once-discarded prototypes, too, meaning you can field operational versions of the fearsome 200-ton Maus tanks, or launch early jet prototypes.

This is World War 2 without the plot points. You take charge of any country you fancy and set yourself a grand plan - play as Portugal and invade Australia, for example. On the way you can set yourself political aims, to rescue your economy from a financial slump, perhaps. Ticking these goals off your charge sheet will improve the effectiveness of the political institutions that run your nation. The new research trees also allow for experimental weapons - not Supreme Commander laser cannons, I hasten to add - but believable weapons of mass destruction, like nukes, and failed rocket prototypes. "I've actually played as Portugal and tried to have a nuclear program and join at the very end and nuke some guy," says Lind. "I managed to get off one nuke on Germany."

The build on show was an early but shows plenty of promise, particularly in the accessibility of that appealing map - a problem point for past Paradox games, "The whole border system is newly developed for Hearts of Iron. You should be able to play almost the entire game on one map mode," Lind explains. Don't be surprised to see a similar system appearing in future editions of Hearts of Iron's sibling series, Europa Universalis and Crusader Kings.

Hearts of Iron 4 is due out early 2015.