[How do you navigate complex video game levels easily? Designer Nerurkar looks at examples from Fallout through Shadow Of The Colossus to examine the top tools for aiding level navigation for players.]
With the ever increasing complexity of our games and our game spaces, the need for support has increased as well. The earliest games often consisted of only one screen.
All the action of the game was immediately visible at a glance -- think Space Invaders or Pac-Man. These are games of (almost) perfect information: you can see all there is to the game. All pieces are on the board, so to speak.
Nowadays, it's a lot different. The ability to display the entirety of the game world on one screen was quickly abandoned in favor of larger environments, through scrolling or leaving one screen and entering the next.
The step to immersive, open worlds in 3D has emphasized this even more. And that's before we add the increasing complexity of gameplay on top of that.
Fortunately, there are tools that can be used to alleviate this situation.
Discrete Navigational Tools
First off, I've separated the navigational tools into two big categories: discrete and immersed. We'll start off with discrete navigation tools first.
By "discrete", I mean that the tools are separate from the environment. They're a part of the Graphical User Interface. This puts them into squarely into the realm of game design. It also makes them stand out -- that means they are noticeable (but can also be obnoxious).
However, the fact that they're abstract makes it easy to use them to transmit more than just spatial information (a position, line, area or volume). For example, the color of a dot on the map might display its health or whether it's friend or foe.
Speaking of maps, let's start with the first tool:
The map is what most of you probably thought of when I wrote navigational tool. It is the most obvious method and the most unsubtle one. A map displays the environment in an abstract (and usually simplified) way to provide a good overview over the game space.
To that end, it often also contains other information on the game state such as the position and state of units or objects in the spaces. This makes maps very helpful for games in which the spaces are sprawling and complex and/or where there's a lot of different information to manage.
For example, in Colossal Cave Adventure, the first adventure game, the player uses text to navigate through a cave maze. The game features no map, since it's all text, but it is so complex that it practically forces the player to sketch one as he plays.
We've learned since then, and the general trend to user-friendliness has ever increased over the past 30-odd years. A step on that road was Doom. For the first time there were complex and immersive 3D environments navigated from a free first person perspective. And since this was not only new to the players but also to the developers, there was little in terms of immersed navigational tools.
To not get lost, players needed a map. And to spare the player the task of drawing it, the game takes over by drawing the automap for him: As the player progresses more and more of the game world becomes visible in his map. This type of map is quite common as it adds to the sense of discovery of the game and shows the players those areas that he hasn't explored yet.
Also noteworthy is that unlike many games, the map in Doom isn't static. Often times, you can activate the map, take a look at the world, and then return to the game to continue playing. In Doom you can bring up the map by pressing the Tab key.
In this new view you can move around using the normal controls. The map moves accordingly while the arrow symbolizing your avatar turns. The controls are a bit awkward and objects or characters (except the player's avatar) are not displayed. Still you can give the map a try in this Flash version of Doom.
Another more recent example of a map is Far Cry 2. In this game's huge open world Africa, the map is necessary to find your targets. What sets it apart from other games is the way the map is integrated into the game. It's not an overlay (as in Diablo) nor is it a separate screen as in Doom.
Instead, your character brings up a map in his hands without you leaving the game and breaking immersion. Just as with Doom, it allows you to look at your map and still move through the world. It's also worth noting that, unlike Doom,the large Far Cry 2 map does not need to be uncovered. A map of the entire gaming space is available from the beginning.
A point of note: the danger of maps that are fully uncovered is that the player might not know where he's been already. In such cases it's often useful to show the entire map but display unvisited areas differently to give hints as to which places to check out if the player is stuck. Ultima Underworld: The Stygian Abyss provided the players with the ability to add comments to the map. This could often be used to mark areas that were already investigated and explored.
In games where discovery is important, uncovering areas of the map can be fulfilling. The player first has to find out about the environment, and sometimes finding pieces of the map can even be a reward in itself.
For example, in Metroid Prime 3: Corruption, the levels are peppered with secret rooms. In this game the player can unlock all the rooms of the current level on his map which makes it a lot easier to find these rooms. Here the map becomes part of the reward system.
A negative point of note about this map, though, is that it is in 3D, which makes it a bit hard to use. It's still quite good compared to other attempts at 3D mapping though. For example, the map in Splinter Cell: Chaos Theory is in 3D, and it's anything but easy to use. Using 3D makes it much harder to quickly understand the complex space -- which partially defeats the purpose of the thing in the first place.
Of course, video games can also create impossible spaces that are very difficult to map in a way that is easily understood: Corridors that return the player to the starting position, even though they are a straight line, or doors that lead the player to different places each time they're opened. In these cases, a map is usually not much of a help, especially as these designs are often meant to intentionally confuse the player.
The next type of tool is what I've dubbed "markers". A marker highlights a certain position or area in the world through a discrete interface element. Kind of like "augmented reality".
Note that this element can be a 2D graphic or 3D model. Also some markers are also only visible when the associated object or place is visible, while others can be seen even through walls and other obstacles.
Markers are very useful to lead the player to a certain position in the world -- even if it is in motion. Because of they are often used to identify important areas of interest, like the positions of teammates or enemies to make it easy to reinforce, engage or evade. Or they draw attention to objectives or other places of potential interaction.
For example, the exclamation mark icons over the quest givers in World of Warcraft are what I would call a marker. They make it easy for the player to navigate to important places where he can interact with the game.
Another example of Markers would be Left 4 Dead, where icons are used to highlight critical resources (ammo, weapons or "peels") and places of interaction (crescendo moment triggers).
L4D also highlights the locations of your fellow teammates with a halo around their forms, with the color displaying their current state. And last but not least, when a teammate can be brought back into action, a silhouette shows where the team has to go to free him or her.
Another well done use of this can be found in Unreal Tournament 3. Here, players new to a team-based multiplayer map can activate animated help arrows which show the way to the enemy flag. This is a good way to quickly teach new players the maps. This idea of marking the path rather than the target is also used in the help system of other games such as Army of Two and Dead Space.
An unconventional example for a marker are the red objects in Mirror's Edge. These change color to highlight the obstacles the player can interact with. This is straddling the line between immersed and discrete tools, since we're talking about objects that are a part of the world. However since these change color as the player approaches, they are definitely interface and not a part of the world itself.
Apart from those examples I also want to highlight -- pun not intended -- another game's use of Markers: Anno: Create a New World for Wii. In Anno, the game sometimes places position and/or area markers to point to certain positions. This is used to show the player where to build his first house or where to steer his ship in order to advance the story.
However, the top-down view in Anno can only display markers when they're on the screen. If you don't look at the destination you have to steer your ship to, then you won't see the marker, which doesn't help much if the player has to find the spot in the first place. And that's where the next discrete tool comes in.
Unlike the marker, which marks a certain spot, the compass is part of the interface and points towards a place in the environment.
When you move, the marker stays with the world; the compass moves with you. The marker displays the target's absolute position while the compass shows its position relative to you.
Continuing the example of Anno from above, the compass is a big arrow which points to the currently active marker. This arrow, however, is only visible when the original marker is not on the screen. As the player approaches the marker, the compass arrow fades out.
This isn't the only instance where marker and compass are closely intertwined. Quite a few games use a marker for important objects. However, you want the player to be aware of their existence and location -- even when they aren't on the screen. This is where the compass comes in.
A quite classical example of a compass would be Call of Duty 4: Modern Warfare. It features a pretty simplistic compass which displays the cardinal points as well as the direction of the next objective. The compass changes as the player turns, so if the objective lies in the center, then it's straight ahead of the player.
Another compass-only system is the teammate locator in Gears of War. Here, if a teammate goes down, a circle pops up on the player's HUD. The circle shows in which direction the wounded buddy is, relative to the player's position.
Yet another compass style, although one that's more indirect, is the Jewel Detector of Far Cry 2. This gadget doesn't use a direct arrow to point to the hidden jewel suitcases. Instead, it features a green light that starts to flash when the player gets close to one of these cases, increasing in frequency as the distance decreases. Additionally, the light stays green if the player is looking directly at the position of these cases.
This roundabout way of doing things helps make the search for jewel cases a lot more fun, as you actually have to go look for them and try to triangulate their position. Notably, the detector is not sensible to differences in altitude: I've found myself standing in an empty room wondering where the treasure is, while the jewel case sat on the roof. Of course, a lot of first person shooters also use a compass system to point a player under fire towards his attacker.
And finally the last example is another odd one: The sword beam from Shadow of the Colossus. It is also noteworthy because the game manages to include a helpful interface without breaking immersion, and while reinforcing the exploration and discovery themes of the game.
Immersed Navigation Tools
As mentioned before, immersed navigation tools are a part of the game environment. Unlike discrete tools which are general interfaces used throughout the game, immersed tools have specific applications in the individual environments. These tools also don't stand out as much as discrete ones and generally aren't perceived as a part of the interface.
This is because they are built out of the components (geometry, textures, lights, characters...) that are also used to build the environment itself, which makes them the responsibility of the level designer. It also means that most of them won't be consciously used by the player. Instead, they serve as subtle instruments by which to guide the player but with this unobtrusiveness comes the danger that some players may just overlook them.
The fact that they're an immersed part of the level also makes them a lot harder to classify. This is why I'm grouping them based on their purpose. I'll explain each purpose and then give a few examples on how to achieve the desired effect with different components.
When using this tool, the aim is to attract the player's attention to a certain location. This is often used in linear level designs with complicated rooms to make it clear where the player has to move in order to continue. It can also be used in less linear levels to highlight important areas of interaction -- such as places that the player will revisit often.
Essentially, the idea behind this is to make this target area look more important and thus interesting to the player, so that he moves closer. This can be done quite subtly, so that the player is unconsciously pulled towards where you want him to be. Of course it can also be done using more blatant means which will most likely cause the player to respond more consciously. As you can imagine, there's quite a number of ways to go about this, so I'll try and list a couple examples below.
If we want to attract the player, we first want to catch his eye. Here, painting techniques help us a lot. After all, painting has been manipulating and steering the human eye for millennia. What's true for paintings is true for levels: Visual contrast is a good method to catch a player's eye. The higher the contrast, the more likely the area is to be noticed. For example, light coming into a dark room from a doorway will attract the player's eye and that makes him a lot more likely to approach the doorway.
In general, light works really well as a method to highlight areas and paths. There's a reason that a lot of Disney theme park rides use light to mark their exits: So the visitors instinctively head toward the light and thus avoid congestion. Believe me, it works; while working on the PSP version of G-Force I had to run through a level to get to a certain point in the game to test something. To get there I had to go past a T-section in a vent shaft area.
And even though I was familiar with the level I always took the wrong turn there. Why? Because I was playing without thinking consciously, and that route was lighted better. And as soon as we had that changed I didn't end up going the wrong way.
To further expand on how important this is, there's also what's called the "squint test": you squint and look at a screenshot of your game. The brightest area is where people's eyes will most likely be drawn. There's even a squint mode feature in the Unreal Engine 3 editor that blurs your viewport to simulate such a test.
Of course, apart from light, you can also use other methods to create a contrast. You could use a unique shape that stands out to attract the player's attention. One arched doorway next to four rectangular ones will look a lot more important. You can also use color to create a contrast. A red door in an otherwise white room is going to catch the player's eye much more than a grey one will.
Similar to how the technique of contrast is informed from painting techniques, this method is too. Here, objects in the environment subtly point towards where the player has to go. The lines of the objects are oriented so that if the eye follows them it will reach the intended target. This works especially well if these lines cross the intended boundaries directly. For example, a plank lying over a chasm will give the player the hint that jumping over said chasm is the way to continue.
"Weenie" is a term taken from the Disney theme park designers. It refers to a large structure in the distance that's clearly visible to the theme park visitor. What these weenies do is give reference points for navigation within the park as whole. Additionally, they also look interesting and important so that the visitor wants to come closer and check them out. The same principle can be applied to level design.
A good example of this in use is in the game Mirror's Edge. Here, the player learns that he has to follow the red objects to get to his goal. And in one map there's a large red radio tower visible in the background. The shape is already unique as most other buildings are skyscrapers but add to this the color red which both stands out and already has some navigational meaning and this Weenie is sure to draw the player in.
Motion is an excellent way to attract attention. Based on how our human eyes and brain work, animation and movement easily catch someone's eye. This increases the effectiveness of a visual component tenfold, as compared to static clues. Whether it's sparks, moving doors or flickering lights -- they all work equally well.
However, using motion also means that player interest is a lot more conscious than with unmoving elements. This also includes scripted events such as a crane breaking down, or a door being blasted off its hinges. These events will grab the player's attention and surely make him want to investigate.
Short cutscenes can also be an excellent tool to focus a players' attention on a certain area. For example when entering a big room, the camera shows the contents of the room and ends up focusing on the closed door at the other side. This clearly tells the player that this door is important and probably the way to leave this room. Of course, this interrupts gameplay briefly -- but a cutscene can communicate complex routes quite clearly.
Adding characters to a level can help the player navigate. For example, in a shooter, the player will be used to attacking his targets and then moving past them. If he's suddenly being attacked from a balcony in a house, then this will focus his attention on that area. He might wonder how to reach this position to get a better vantage point, or to grab whatever items his enemies will drop.
Whatever the case, the player now knows that there's something up there which makes him likely to investigate. Additionally if the game features some sort of hit-direction compass then the player also gets the direction of his attackers as a clue. This makes this work even if the player's not looking at them directly when hit.
Another way to use characters is to use friendly units to show the way. If your allies are moving along the planned path and through a doorway, the player will take notice of that route and probably follow them -- though only if he notices them leave.
For this reason it might make sense to have one character leave through the doorway, and another one take up a position next to it. That way, even if the player misses the initial character leaving he can still spot the second one and come to the conclusion that the doorway is important.
Be careful with this though, as you don't want to make the player feel like he's only following his allies and not exploring himself. Also, you of course need a robust AI that doesn't get stuck or make other mistakes.
Just as with characters, pickups (aka power-ups) will draw the players' attention. One reason is that pickups are most often highlighted to be clearly visible: Maybe they even rotate or pulsate. Either way, they often stand out visually. Add to this the fact that most players will want to pick them up and you've got a perfect tool to attract players to a location or to pull them along a route. This can also be used well in multiplayer maps where there usually are lots of items around.
In G-Force, we've used this technique to help the player find the way to continue. The environment of many levels requires the player to frequently ascend and descend, however the camera cannot be used to look up or down in regular gameplay.
Because of this, the tops of shelves or tables might not immediately seem like destinations. However, if he sees a pickup rotating on the table, the player is much more likely to investigate. The rotating pickups make the route visible even at the sides of the screen.
This method is used to help the player with his ability to orient himself within the environment. It does so by distinguishing different areas from one another. This helps the player identify them and thus gives him a sense of position in the overall level. This only really makes sense in non-linear worlds such as hub-levels, multiplayer arenas or large open worlds.
Landmarks are immediately visible features of the environment. While within the area the landmark is often in view. This way it can give identity to a location. In smaller maps it could be a statue or maybe a large red truck. In bigger maps it could be a prominent bridge or a skyscraper. As you can imagine, landmarks and the weenies mentioned above can be one and the same object -- to both attract the player to a location and help him identify it.
Unlike the landmark, where there's one dominating feature, using style means that the difference permeates an entire area. It could be a different architectural style, indoor vs. outdoor or plainly and simply a different color through textures, light or post processing effects.
It doesn't matter, as long as the different areas are distinct enough for the player to easily distinguish and remember. A downside is though that you still have to teach the player the relative position of the different locations. It's not really evident to a player standing in a back alley that the little pirate village is right next to the dark woods.
The guide method is building actual guides into the map itself. These guides clearly lead the player along to where he wants to be. This also makes them quite obvious since players need to consciously see and use them. Examples would be signs or colored lines throughout the level. In some cases there are even maps of the level displayed as textures on the wall.
Of course this kind of tool only really makes sense in non-linear environments where there are multiple different places of importance to reach. Especially if the places are complex or there's lots of different ways to get from one to the other. In linear levels there's little need for this.
Valve's Team Fortress 2 is an obvious example for guide signs. The game features complex multiplayer maps that sometimes even change during gameplay. To help the players learn and cope there's a lot of signage throughout the levels.
These signs are clearly visible and generally make it easy for the player to figure out which route to take to get to a certain area. They also fit in well with the visual style and theme without seeming out of place, even though they are clearly huge.
Portal, another Valve game, is a good example of lines. Even though the individual areas aren't too big, the interplay of the different interactive elements can be complex at times. To help here the game visualizes logical connections, such as between a button and a door, by using glowing lines. These are a great help when navigating the environment.
They also have the added bonus that they transmit a lot of other information as well, something that's generally hard to do with immersed navigational tools. These lines also display the states of the different interactive objects (button pressed, energy on...) and their links (button A opens door B).
Lines are also used to great effect in the apple orchard level of the horror game Condemned: Criminal Origins. Playing an FBI investigator, the p