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For this week's Developer Blog, we gave Senior Designer, James Tsai, the opportunity to let loose on the topic of "Challenges of Designing an Open World". Obviously, this is a very broad topic to go off of, but James is able to gather his thoughts together and give all of us a great look into the process behind open world design, along with the challenges and accomplishments found along the way.

For his full story, hit the jump.

Introduction

I’ve been staring at this blank page for about twenty minutes now, trying to figure out how to write about all the complexities of open world design in 1500 words or less. It’s a tall order, but appropriately metaphoric: making a fun, fulfilling open world is such a large task that you often have no idea where to begin. So my solution to this writers’ block is to do what I always do: ramble on until someone tells me to shut up.

The freedom that an open world affords players can present a real challenge for designers because we’re very often used to gameplay that’s a tightly controlled experience. In our past first-person and third-person shooters, it was easy to funnel players down a hallway and throw enemies at them or surprise them with a hole blown in the wall at a precise time. And conceptually, there was no problem with exploring the land of baby bunny rabbits one minute and then viewing demonic sexual immodesty in the pits of hell the next, as long as there was a cool cinematic in between.

In an open world the rules are different. The player’s tools are going to be used for a broader range of purpose than in a linear shooter and it’s far tougher to anticipate their location in the environment, which needs to be cohesive and interactive. The “sandbox” comparison is clichéd but accurate, because you’re essentially plopping them down with a bunch of toys. But instead of a pail and shovel, the player has big guns and fast cars. And at one point, a truck that shoots poop. So how do you design for so many player choices?

Open World Design in Missions

A good way to illustrate some of the design challenges we faced is dissecting some gameplay. At times, mission design in SR2 got tricky because there were competing game principles to consider. Missions are our primary tool for advancing the game’s narrative – they set up some of the coolest moments in the story, so we needed to have the players doing certain things in certain places at certain times. And yet at the same time an open world demands that a player be able to do things without restriction: take unpredictable paths to destinations, use different types of vehicles, or equip weapons with different capabilities.

Bryan Dillow, one of our gameplay designers, created a mission that demonstrates several of the lessons we learned in SR2. Every mission was tested, edited, tested again, edited again, tested by more people, edited again…you get the picture. Since I hate spoilers as much as the next gamer, I’ll keep the story details out and focus purely on the mechanics. I’m still bitter someone told me the ship sank in Titanic.

Anyway, the player’s job in this mission is to hit a convoy of buses. These vehicles travel from their start point in the city and must be taken out before they reach their destination. The pictures show just a few of the ways players can accomplish this:

Ambush	Pursuit
Bash	Intercept

Simpler can be Better

I love what Bryan did here because it illustrates one of the keys to open world mission design: simpler core objectives give players more freedom to be creative. Bryan tells the player to destroy the buses before they reach a certain point and lets them figure out the rest. If he had demanded that players abduct someone on the bus or steal the bus itself, they would have been deprived of a lot of options since keeping the bus intact would have become a precondition for success, effectively forcing everyone to do this part the same way.

With the more basic objective, players can chase down and shoot at the buses, use a rocket launcher to ambush and blast the convoy, find a makeshift battering ram to use against the lead bus, or find an assault helicopter to hit the vehicles with from above. Those are just a few of the creative solutions that exist; having fewer limitations leads to more interesting and rewarding scenarios.

Another good example to look at is how the buses’ route affects the mission. Bryan used a straightforward course that took the convoy through lots of intersections to give the player more choices. Too many twists and turns would have bottlenecked the action into one or two prime spots and given the AI drivers fewer escape routes, increasing their predictability and reducing the number of viable player strategies.

Let the Game do the Work

Making an open world game is no small task, so taking advantage of work we’ve already done is always a plus. The programmers and designers created a lot of general use systems to help make Stilwater a more interesting and fun place to play in, many of which come in handy during mission design.

The notoriety system, in place since SR1, is one of the most oft-used and straightforward examples of this. When running around the world, players can cause mischief ranging from small things like knocking over fences to bigger things like sticking a satchel charge on someone’s crotch and blowing them up as they run screaming into traffic. The player earns notoriety points for actions like these, and as they reach higher levels of notoriety the game spawns escalating degrees of law enforcement nearby and sends them into the fray, where their combat AI takes over. This happens both inside and outside of missions.

In Bryan’s mission, logic dictates that the police react once the player hits the buses. Rather than detect or guess where the player is along the convoy route when that happens, Bryan simply turns the notoriety system on and sets it to the necessary level to get the desired police response – level three for SWAT vans, level four for helicopters, etc. I don’t have a figure for what the equivalent number of satchel charges on the crotch that would be.

What we give up by doing this is precise control over from where the police will come from and when, but since we spawn them in aggressively enough it’s not a problem. And given the size of Stilwater and the improbability that the player will be exactly where we want them to be at a given moment, having to spell out each officer’s location would have been be far more trouble than it was worth.

Difficulty is Easy to Influence but Tough to Control

Making sure this mission wasn’t too tough or too easy was a big task. We have global difficulty levels in the game now, but whether someone chooses to play on Casual or Hardcore, there was still a lot of tweaking that went into missions to ensure the right amount of challenge. With all the different approaches a player can take to beating the game, we quickly found that balancing missions was less of an exact science and more like herding kittens without pants on – you can push things in a general direction but you have to accept getting scratched...just watch out for the BIG scratch. That’s a stupid comparison, but no one has told me to shut up yet.

This particular mission had several factors to consider when balancing. As mentioned before, the police get pissed at the players when they hit the convoy, and we then set the notoriety to a level that is appropriately tough. The problem here is that “tough” means different things to a player on foot as opposed to one sitting comfortably inside an armored helicopter.

Complicating matters is that in an open world, you can provide lots of options for mitigating difficulty but can do very little to guarantee they’ll be used without being heavy-handed. During testing, people frequently told us that destroying the buses was too hard because they didn’t have enough ammunition, or that the notoriety response was too severe. There were nearby options in the mission that players could use to address these problems: the weapon store, and the notoriety-eliminating “Forgive and Forget” drive-thru. But we weren’t explicitly directing the player to these locations in between objectives, so it didn’t occur to most people to use them at all.

Thus we would typically err on the side of being easier rather than difficult for many of the same reasons discussed earlier about mission complexity. The harder a task is, the more likely you are to need a certain weapon or vehicle to complete it, which cuts down on player choice. For example, we made the amount of damage a bus could sustain low enough that a player doing a drive-by would be successful even if that made it extremely vulnerable to aircraft, since otherwise we’d essentially be telling players, “You will only beat this with missiles.” And because we balanced damage and notoriety without the expectation that the Forgive and Forget or weapon store would be used, resourceful players who do visit them reap a very impactful benefit, which works out better anyway.



Closing

So that’s a look at just a few of the challenges and lessons learned in open world design on SR2. It’s been a lot of fun making the game and everyone on the team became a better designer along the way. For all of us, it’s been a learn-as-you-go process where you’re constantly pushing yourself to improve even after you’ve gained a lot of experience, like cooking or stripping.

- James Tsai

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