Whatever you think of the games it produces, the production line that serves Ubisoft’s Assassin’s Creed series is a marvel of process, coordination and engineering. The machine is prolific. That the publisher manages to organise its disparate studios to deliver a cohesive game each year that includes at least one entirely new city at a different point in history to its stablemates is a feat no other company can match not with this kind of unflinching frequency.

For Assassin’s Creed Unity, the first title in the series exclusively for new hardware, a great many hands were drafted in to build French Revolution-era Paris. It is, in fact, a game of two halves in the most basic sense: the cobbled streets and missions on one side of the Seine have been created by one studio, and those on the other side by another. The joins are, miraculously, imperceptible.


But there is an issue with such well-oiled and anonymous production machinery: the sense of the individual craftsmanship that goes into recreating a metropolis in all of its period glory can be lost. Perhaps it’s for this reason that creative director Alexandre Amancio is eager to report that a single person built the cavernous cathedral at Notre Dame, the cultural centrepiece of the city and the game. In a virtual city built at one-to-one scale with the real Paris, this astonishing task took its creator an entire year to complete 5,000 hours in total for the woman who meticulously placed each one of its stones  and columns by hand, according to Amancio.

Such is the cost of building games of this scale today. “Up until this point in history, we were gated by the technology in games,” Amancio says. “But now, for the first time, manpower, talent and time are the primary constraints. That becomes your boundary. We’ve had ten studios working on [Unity]  to realise the game we wanted to make.”

The fruits of that combined labour and the benefits of fewer technological boundaries are immediately obvious. Crowds are a clear leap forward 18th-century Paris hums and bustles with a jeering, raggedy throng that both impedes new protagonist Arno Dorian’s progress and provides a thicket into which he can disappear when being tracked by the local gendarmes, or other roaming hostile factions.

Typically, according to senior producer Vincent Pontbriand, these crowds are capped at 5,000 bodies, but in one scene that number jumps to 10,000. “The reason we limit the size of the crowds isn’t so much to do with technical limitations as it is to do with the difficulty that the player might have with navigating a group of this size,” he says. Slink Arno through the bodies and take to the rooftops and  Unity ’s next technical marvel is revealed. This is the largest city in the series yet, comfortably bigger than the landmass of all  ACIV:  Black Flag ’s archipelagos combined.

The skyline is one of proud spires, jutting edifices, and smoke curling into the sunset. Each district has a distinct character. There’s the Halles, full of chaotic markets; the slums of Ventre de Paris; and Île de la Cité, which is packed with vast religious constructions. Behind this backdrop lurks the coiled tension of the period, the social and political upheaval made plain by public hangings, a menacing police presence, and the slogan bearing banners (‘La liberté ou la mort’ freedom or death) that hang from the rafters.

It’s not only the courts and cathedrals of Paris whose insides have been decorated in revolutionary colours. One in four residential properties has also been fully decked out with an interior Arno is able to leap through an open window, run through the top floor of a house and self-defenestrate on the other side as part of his parkour routine and almost every major landmark in the game also has an interior finished to a high standard. “Being able to do all of this without loading screens is something we couldn't have done before,” Pontbriand says. “The game would have had to be completely different if it was appearing on previous generations of console hardware.”
There’s a sense that you can run and climb anywhere, rather than along funnels
Working at such a large scale brings problems beyond interior decorating.
“The more realistic and complex you make something, the greater the risk that you expose its limitations,” Amancio says. “When you have crowds of this kind of scale, you expect them to behave like humans. That puts tremendous pressure on the AI team. That in turn pressurises the performance team, [since] every time you have an AI running onscreen, the game’s performance is affected.” The limitation then becomes one of balance. “The skill is in an organic process of balancing ambition with reality in order to figure out what to push and what to dial back.”

The changes to the architecture come with some major amendments to the way in which parkour works. The introduction of a ‘parkour-down’ button which allows Arno to control his descent from the rooftops rather than being forced to leap into a hay cart is a surface level change, but the underlying system has undergone a great overhaul. In particular, lateral movement when climbing the exterior of buildings is far smoother.

“In previous Assassin’s Creed titles, the parkour was achieved by using two separated systems that, in truth, didn’t interact all that well,” says Amancio, who also led the team on 2011’s Assassin’s Creed Revelations. “There was the ‘climb’ mechanic, which allowed the character to slowly find hand- and footholds based on a 30cm grid that was overlaid onto the environment. Then there was the parkour
mechanic proper, which allowed the character to string together more dramatic manoeuvres by, for example, leaping from a small crate to a large crate to a pole, and so on.”

The parkour system was designed to work within ‘highways’: long series of objects that would encourage fluid traversal. But as soon as a player left the pathway, the game would switch to the more plodding climb mechanic. “Flow is lost and there’s a grinding of gears as you switch between the two,” Amancio says. “Our main goal has been to bridge the gap between those two systems in order to create a more consistent flow effect. We’ve had a dedicated team working to ensure that any
architectural element can be perceived as a parkour ‘ingredient’ by the system. Beneath the hood, the system predicts what you might do next it needs to do this because the control system is so simple. It tries to be prescient in order to make those paths and decisions ahead of time to create fluidity.”

The effect is striking. While there is more of a learning curve to how you use the various inputs to traverse the city, once mastered, there’s a sense that you can run and climb anywhere, rather than along the designers’ funnels. This feeds into the team’s desire to encourage greater exploration in Paris something that, Amancio says, the series has unexpectedly failed to do in the past. “In previous titles, we’d notice from the heat maps we’d generate to show where players were spending time that there would be hotspots of activity, and low density everywhere else,” he says. “People were not playing an open world game so much as playing a linear level within an open world.” This racing between mission markers was so pronounced that Amancio claims the team could have placed invisible walls all over past cities and most players would never have noticed.

Unity’s developers reached the conclusion that the problem derived from a conflict between the setting and the drama. The goal of a sandbox is to have players relax and explore, which is at odds with a narrative arc that’s constantly pushing you forward. There is also the argument that the series’ busy work can be overwhelming an Assassin’s Creed map is often a mess of icons that indicate treasure to collect, snippets of narrative to uncover, and collectibles. It is, perhaps, no wonder that many stick to the main drama as a way to make it through all the distractions.
“For the first time, players are treating the city like a world and not a series of levels”
 “Games like Watch Dogs have been perceived as overwhelming,” Amancio says. “They reveal everything on the map. The issue with that is you’re telling players that the space between icons is essentially blank. That breaks the illusion of the open world. One of the ways we try to tackle that is balancing what we show on the map, and what we hold back to be revealed as people explore.”

Another solution comes in the mission structure, which is more freeform. It will, in fact, be possible to take on missions for which Arno is ill equipped. “We mark these with a difficulty sign,” says Pontbriand. “The player is able to tackle a challenging mission, but they are equally aware that it will be beneficial to do some other things in the city in order to improve their equipment or skills first. The new system is trying to expose rather than impose.” Amancio believes that the new system has empirically been successful: “When we looked at the first heatmap from Paris, it looked like pure chaos,” he says. “For the first time, players were treating the city like a world and not a series of levels.”

Will there be  enough variety, though? Black Flag  was celebrated for its seafaring piracy, but there is no such headline diversion in  Unity , which takes place entirely on land. The team believes the variety is more subtle, but no less meaningful. Missions now reward more inventive means of assassinating a target, for instance. In one scene you must kill a mark at a sermon in Notre Dame. It’s possible to air assassinate him with a blunt drop from the cathedral’s rafters, but if you take the Hitman-esque approach of murdering him while he sits in the confessional box, you’ll be rewarded with useful information you wouldn't have received any other way. 

Combat has been made more punishing you can no longer counter kill indefinitely and Pontbriand says that drawing your sword should only be “a last resort. There are neat tricks to deal with a lot of guards, but it’s deliberately tough.” Instead, Arno’s stealth abilities have been powered up to encourage a more considered approach.

Away from the main missions are murder investigations in which Arno gathers clues at a crime scene in order to make an accusation, losing points for a wrongful charge, and the Café Theatre, Unity’s take on ACII’s villa, with cafés that can be purchased, furnished, used to generate income and franchised. “Every mission, every heist, every murder mystery and treasure hunt gives you money, weapons and gear,” Pontbriand says. “This empowers you to approach situations in different ways,
because it all feeds into the same loop.”

While Unity is a game with a predestined story to tell, Amancio hopes that its network of interlocking systems will generate personal tales for each player. “We have hundreds of contracts and side missions so that even our team members are constantly finding new stories,” he says. “That creates a unique narrative for each player in terms of their route through the game. But when you add into that a layer of unscripted chaos, I think the most interesting stories will turn out to be those that the players tell.”