The crouch that changed Assassin's Creed

The protagonist in Assassin's Creed Unity can crouch at will, making him something of a god-like figure in Ubisoft's ongoing rewrite of history. Arno traverses a dense and dirty recreation of 18th-century Paris, packed with jostling citizens screaming for a revolution. But as massive as the city is, with the Notre Dame de Paris looming over pockets of opulent residences and rain-slick squalor, the game's struggles happen on a small scale, crouched close to the ground.

"The engine was ... I mean, we rewrote like 6 million lines of code for this," says Alex Amancio, the creative director who speaks for the work of ten different Ubisoft studios. "It's not a joke."

Crouching really is a big deal if you've been playing Assassin's Creed since day one, even when it sounds like the most mundane ability in a series where you routinely clamber over historical landmarks. In earlier games, the hero's stealth state was contextual, and only permitted if the environment allowed it via a haystack or a lush stealth shrubbery to hide in. With that clumsy behavior untangled from the engine, the developers of Unity are putting effort behind Assassin's Creed as a stealth game the way we heretofore could only imagine it to be. Moving invisibly has always been oafish in Assassin's Creed, implied and outright imagined as you somehow vanish into a cluster of four people. It fell under suspension of disbelief.

"Our navigation seems very simple and very accessible, but to do this, it means that the system is calculating, before you're actually moving, where the possibilities of where you're actually going to go," Amancio says. "And this is why a lot of people, from previous games, they felt like, 'I didn't want to go there and got detected.' We're trying to favor flow. We don't have a vehicle like Grand Theft Auto, a car and then a character – the assassin does both. So we need to favor flow for the traversal of the city, so a lot of times when you're trying to be stealthy the system is trying to favor speed and flow, and this is why this stuff happens. By creating the stealth mode, what we're actually doing is changing the way the navigation is working, because we know that you want to be stealthy."

The additional precision over stealth – in the sense that the game now knows you want to be quiet – is having a radiant effect on other parts of the game, Amancio says. Guards use a more human perspective to spot you. When you escape direct line of sight, either by crouching behind cover or dropping a smoke bomb, they'll investigate your last known position (displayed as a three-dimensional outline of you). "The initial loop that we've always wanted is you plan your mission, you seek your way in, you do your deed, kill your target, you vanish. The problem is an infinite number of times along that way you can get detected," Amancio says. "Every time you get detected, stealth is dead, because detection is the fail state of stealth. And then every time you break into combat and usually, because combat is easier, every mission finishes in a brawl. What we've tried to do is create the loop where, you try to stealth your way in, use strategy, you get detected, if it degenerates you disappear, you break line of sight, you go back to the rooftops, you plan and you strike again and you do that until you succeed."

This advancement is also seen as a return to basics for Assassin's Creed, which has become increasingly layered with multiplayer modes, naval combat, homestead management, barrel creation, and all manner of activities littered throughout the open world. It's strange to think it's taken this long to truly formalize the heart of the game – stalking people of importance, planning their assassination and destabilizing the status quo. Following a target, learning their pattern and discovering secret routes have been options since the first Assassin's Creed, but they were poorly illustrated. It didn't feel like it was the right way to play the game.

With Assassin's Creed Unity, major missions are explicitly disassembled into opportunities for the exquisitely dressed assassin, Arno. Some might require multiple steps, like stealing a key from a patrolling guard in order to unlock a window high atop your target's location. The catacombs beneath Paris might lead him right beneath his templar prey, or a kindly priest might unlock a special stairwell for you if you can find him. These options for a single mission are now explicitly encouraged, Amancio says, and given a slight nudge by a much harder combat system. "Because I strongly believe that players want to look around, they want to explore, they want to create that stuff, and they're willing to spend time and invest time to do that," Amancio says. "But I think players are unwilling to spend even one second if they believe that's wasted time. If they think the developers want them to go through the front door, kill everybody, stab the target in the face and then leave, that's what they're all gonna do. In a lot of games, that's exactly what they're telling you. In order to clarify that we actually want something different, we decided to give these key phrases that are extremely clear, they tell you what you can do. The stats are just giving you permission to play around and explore, they're just ... listen, this is here, have fun."

Though the danger of fighting can be dulled with the right equipment upgrades, a quick escape has always suited the game's traversal system. There is risk in changing how it works and rewriting so much, Amancio admits, because people get used to what they like. "One of our challenges was actually making it feel like it felt before, and then going from there," he says." Because it could have felt really different very easily because we rewrote so much. Studios are needed for that, right? This is the first one, and then you cycle, building the engine, experimenting. For a lot of things we found ourselves in completely unknown territory for the first time again."

How much risk can there really be for such a large effort? Well, just as Amancio says, Assassin's Creed Unity does feel different. Instead of climbing on autopilot, you now hold the right trigger to automatically clamber over everything on your current level, and then use B (or Circle) to rapidly descend or A (or X) to quickly climb higher. The buildings in Paris utterly dwarf you, so the controlled descent takes a lot of fear out of heading downward. And once you're down safely, you can marvel again at Ubisoft's expert habit of making cities that feel alive with people selling goods and going about their bustle on the street.

Though Unity feels different, I don't think it feels good yet. At a fast pace, Arno often climbed the wrong way, got stuck on banisters or would leave himself dangling from a rooftop overhang, unable to continue until dropping. The framerate seems to have a lot of trouble keeping up with Unity's huge crowds and vivid lighting, which impacts Arno's responsiveness. And though the stealth mode is effective and snapping to cover worked well on every surface I tried, unsnapping felt too sticky. In one of my assassination attempts in Notre Dame (which looks beautiful), I was constantly foiled by stacks of furniture which were hard to read as climbable or unclimbable. A guard spotted me crossing a cable near the cathedral's ceiling, and proceeded to give chase by walking off his balcony and falling to his death. Clearly, the Xbox One version I played was still in progress, and the team still has some work in making the game feel smooth.

The complexity of movement, whether you're crouching or not, is also fundamentally tied to the game's ambitious co-operative modes (competitive multiplayer is not happening this year). There are sets of two-player story missions in the world, as well as four-player heists, the latter of which comes from last year's Splinter Cell lead, Ubisoft Toronto. Once you find the right location and initiate the mission, other Arnos from friends or matchmaking join your game seamlessly, like travelers from an alternate universe.

"People don't understand that just adding co-op, for example, replication, the world that you see and the 5,000 NPCs have to be the same that I see," Amancio says. "Unlike other open-world games where crowd is just sort of ambiance. our crowd is one of our gameplay pillars, it's part of stealth, so it has to be the same or else the experience isn't the same, so even combat, the fact that NPCs recognize more than one entity, the fact that you can actually deal with multiple people striking the same entity. All of that stuff meant that every single one of our pillars had to almost be rewritten from the ground and redesigned."

In co-op, where sneaking and combat feel more improvised and dynamic, Assassin's Creed Unity feels better. Targets can be easily shared with other players, and unique abilities, like healing or an instant disguise, can help a team recover from embarrassing missteps. Combat really is tougher and more exacting on health, but it also makes these missions teeter on the edge of a fun sort of chaos. The smoke bomb is perhaps a little too powerful, though, since four assassins rushing into a cloudy room can make quick work of just about anyone. It's a pattern the game might do well to discourage just a bit.

But then, that doesn't seem like the spirit Ubisoft is shooting for in Assassin's Creed Unity. It's in rough technical shape right now, in my opinion, but Amancio insists the game will hinge on how well everything – co-op, new navigation, new mission structure and, of course, crouching – comes together as a whole. "It's essentially stuff that piles on, and one single feature is easy - to press a button and have the character go into crouch. It's all the different hundreds of systems that tie into that that become complex," he says. "This has a lot of different systems that are just piled on. Every time you change one it's not necessarily bad, or creates a problem or bottleneck, it's the number of ... the actual tree that spreads from that decision that then affects everything else."

Assassin's Creed Unity is out on PS4, Xbox One and PC on November 11. Images: Ubisoft.