The original Uncharted also had the occasional flash of stealth gameplay, with bespoke animations and combat techniques where Drake could surprise enemies from behind and take them down silently. This was massively expanded in the sequel and became a core part of the gameplay.
"We also started work early in pre-production in improvements in AI that let players choose to engage with our combat setups in an action-stealth way," Lemarchand explains. "We gave our enemies an 'investigate' behaviour that they use when they hear or see something unusual and also a 'search behaviour' they would use if they had seen Drake but didn't currently know where he was. These techniques paid off right through the whole player experience so it was really good that we got started with them early in pre-production."
The final piece of the puzzle that was established in this phase of development was the methodology in handling Uncharted 2's epic set-pieces.
"One particular sequence from Uncharted: Drake's Fortune had stuck in our minds and really fired our imaginations," remembers Lemarchand. "It's a simple sequence from the Island Waterfall where an explosion near a truckful of enemies flips the truck and forms a bridge.
"It was a really dramatic moment, like something from one of our favourite action-adventure movies, and played out almost entirely in gameplay. It made us feel that we had only just begun to scratch the surface of what was possible in terms of delivering a truly interactive cinematic experience and we thought that making bigger set-pieces and moving away from so-called Quick Time Events was probably the right way to go."
The Dogs realised that expanding this concept into truly spectacular set-pieces would involve a huge amount of work, and the first section they tackled was an early rendition of the collapsing bridge from the monastery level near the end of the game. The team realised that these sections would be incredibly time-consuming, and specialist technical scripting designers were hired to make sure enough manpower was on tap to get the job done, but even then, it was a massive task that dominated the production schedule.
Meanwhile, other team members in the Naughty Dog kennel spent the pre-production cycle simply... building stuff. According to Lemarchand, during the first Uncharted too much time was spent theorising about game design rather than getting on and doing it.
"We did our best to hit the ground running with Uncharted 2," he remembers. "The team was keen to keep up the production momentum built up over the previous three years with Uncharted: Drake's Fortune and using the first ideas we had, everyone could get down to creating art, implementing game mechanics and laying out levels almost immediately. By the time we hit full production we were in much better shape than we had been at the same stage during our last project."
The only real risk the team took with this approach was what Lemarchand describes as reaching a "soft end" to the pre-production phase, as the team transitioned into the full-on development of the actual game. All of the game-building going on had resulted in the all-important Macro design not being as final and complete as the team realised they would have liked.
"It took us a long time to figure out how the story would come together in the monastery in particular," Lemarchand muses. "When you play it through you might notice that there aren't really enough strong story beats there to match the length and the intensity of the gameplay and it's the first place in the game where the pace of the experience begins to lose steam a bit. Of course as soon as we realised what was happening, we scrambled to patch things up. At the end of the day we had committed too much to the level in terms of final art and we couldn't really bring about a perfect fix."
The lesson here for Naughty Dog was to firmly establish all elements of its Macro design before moving into full production. The gameplay should match the rising and falling rhythms of the story, and weak elements of the Macro need to be firmed up before too much in the way of final art is completed. Lemarchand pinpoints parts of the game where level design starts early and story design finishes late as the areas that should get special attention.
April 2008, and the Naughty Dog team move onto full production of Uncharted 2. Now Micro design is created to accompany the Macro. Levels take shape, play mechanics are developed and the game proper begins to take shape.
"We do this Micro design work on a just-in-time basis, a bit like Gromit laying out the toy train tracks only just ahead of himself in 'The Wrong Trousers'. We had gotten a leg-up with the level layout during pre-production and we were just far ahead of the team that we were able to move forward smoothly," says Lemarchand.
"Even though this way of working might seem like a seat-of-the-pants way of doing things, in truth we think that it's the way that a lot of game development happens and we just have the courage to make it an official part of our process."
The team's "just build it" approach saw the traditional paper map method of level-creation taking a backseat. Levels were sculpted in a basic 3D form, dubbed "block mesh" by the team.
"We started by sketching out an experiential flow for the player then meeting with the artists and programmers who would be working on the level to get their input and ideas," Lemarchand explains. "Then we just started building simple geometry in Maya, roughing out a physical footprint for the level and playtesting it on literally anyone who came within arm's reach and getting constructive input from as many different people as possible.
"We started to do paint-overs with our concept artists to move our conception of the look of the level along and after that, it was simply a question of iterating as much as quickly as we could before handed off the block-mesh to our environment artists who would continue to iterate on the level, making progressive detail passes until we eventually arrive at the finished art."
The only issue with this approach was what Naughty Dog came to see as missed gameplay opportunities that more traditional level-planning may have brought to the table. Also, what a level designer envisaged as a blank wall could end up getting a lot of fine-detailing, making it look more important and more interactive than it was actually supposed to be.
"Unfortunately this is a pretty serious problem in Uncharted 2, especially in detail-rich areas," says Lemarchand. "In future we're going to try to find a better balance as regards these aspects of our layout process and we're going to have more of a layout focus on realistic architecture earlier and how its details will affect the player's experience."