Lines of Communication

Communication is a tricky issue for video games. Being interactive systems that use visuals to communicate the majority of information to the player, video games can most easily be cluttered or cleaned up with visuals. Games like Pong are very simple. You can see both paddles and the ball on the screen at all times. The score and the sound effects are particularly minimal as well. For the average player, nothing happens in Pong that goes unnoticed. Anything more complicated than Pong, and player attention is split between different elements forced to dance back and forth to keep up. The harder you focus on staying alive or achieving the next objective, the more your mind will develop a sort of tunnel vision inevitably filtering out possibly important information. 

For most real time games, there's too much going on in the game to think/talk about everything as it happens. If you've ever listened to the commentary of a Smash Brothers, Street Fighter, Halo, Modern Warfare, or StarCraft match you know that there's no way the commentators can even cover 1/10th of the action because the games move so fast or have so much going on at once. This issue of information overload is exacerbated in 3D games. Fortunately, designers have implemented features that swing the advantage back in our favor in the battle of information warfare.

The following is a list of highly communicative visual elements.

Even in this busy battle scene, the lines of communication are clear.

• Thinking Machine 4. If you ever wanted to know how a Chess AI thinks or how it weighs out decisions, then this game is for you. Each line is color coded displaying a simple calculation of a move possibility. The thicker a group of lines, the more the computer is "thinking" about a particular move/piece/position.  
• FF12 colored lines. These lines give the player a visual representation of what each character/enemy is targeting and the rough timing of their attacks. With this feature, the player can be informed of incoming/supporting attacks even when the characters/targets are not on the screen. 
• Healing Beams.  In Section 8 and Team Fortress 2, healing beams are visible to all players. This makes it clear to everyone exactly what's going on between the healer any his/her targets. 
• Resident Evil 5 laser sight. In a chaotic co-op skirmish, sometimes there isn't enough time to communicate to your partner. Instead of trying to say "don't move! I got a good shot on the guy behind you and then I can take out the guy who's trying to bite your neck!" the laser sight does most of the talking for you. When playing, you can clearly see where your partner is aiming. That little bit of information goes a long way with zombie crowd control. The snipers in Mirror's Edge, and the snipe/Spartan Laser from Halo 3 have a similar effect. 
• StarCraft2 rally points. When you set a rally point for your units, a line is drawn between the starting and ending points. This feature is especially useful when viewing replays of matches. Even though you don't know what a player is thinking, you can read the rally points as the plan or intent for upcoming units.
• Splinter Cell: Conviction's Last Known Position. The last place you're spotted by NPCs is represented by a ghostly outline of the player character drawn in the game world. This feature makes it easy to see and understand exactly what the AI is thinking. 
• Orbox B. Traced pathways. Every move you make in this puzzle game leaves a trail behind. If you go over the same space twice, the space is marked accordingly. When solving complex levels, having these trails around becomes very convenient for avoiding mistakes that jettison you out into space.

Of course, HUDs are naturally designed to communicate key pieces of information. From the "X" mark in the locations where allies are killed in FPSs, life bars, to mini maps, HUDs typically make playing games easier. As far as mini maps go, my favorites are the maps in Zelda Phantom Hourglass, Spirit Tracks, and Mario Kart DS.  Click here for more on DS maps. 

Update on Monday, May 10, 2010 at 6:23PM by Richard Terrell (KirbyKid)

For three more excellent examples...

• The Striker ball from Mario Strikers Charged. In this soccer hockey hybrid type game, passing or charging the ball increases its charge. The higher the charge on the ball, the stronger and faster shots on the goal become (among other special effects). This naturally increases the likelihood that such shots will go in. The charge also fades with time (see video here). In the original game for the Gamecube, the charge of the ball was invisible to players making it really difficult for me to understand why all of my friend's shots when into the goal and none of mine did. In the sequel, the Wii version, the charge has multiple stages of charge indicated by the glowing color on the ball itself. Shooting the ball with different levels of charge also makes different sounds, but the visual is the most important. When the ball is white hot watch out. 

• Rhythm Heaven animations. This game is a highly polished music rhythm game. Just about everything you need to play each level perfectly is cued up via audio cues. Along side the audio cues are brilliantly designed animation cues that are highly effective in communicating whether the player is too late, early, or if they hold too long. In some levels, you can compare your characters animation with the NPCs on screen. If you're exactly on the beat, your animations will blend in perfectly. For other levels the visual cues more unique yet still very intuitive. Take Fillbots for example. Notice how the fuel fills the robot up. When it reaches the top, you should release the touch screen button. If you get it just right, the bot flies away with joy. If you release too early, clearly the fuel inside the bot won't be at the top of its head. If you fill it up too much, the bot's face shows distress as excess fuel sloshes out the top. If you fill it up way too much, the bot will explode. Finally, the juice dispenser pulses with the beat like a metronome. 

• Mario Kart Wii Drafting/Slipstream lines. (video here: see 1st example and at 4:10) In Mario Kart 64, it's possible to gain a speed boost by taking advantage of the lower pressure zone that trails behind bodies moving through a fluid. In real life racing, this is called drafting. Unfortunately, it's very difficult to do in MK64. Not only is it hard to stay perfectly behind another Kart, but the game gives the player no indication if they're doing it right unless they successfully complete the boost. Because of this design, drafting in MK64 was rare and mysterious for me. In Mario Kart Wii, little wisps appear in front of your Kart when you're within another Kart's slipstream. The more lines, the more perfectly you're lined up. Hold the position for about 3 seconds and you'll get a free drafting boost. This little difference in visual design makes all the difference.