World 11

Interface

How a game speaks to the player and how the player answers: HUDs, menus, saves, teaching and accessibility.

Everything between the game and the person playing it is interface, and most of it is only noticed when it fails: the health bar you can't read from the sofa, the subtitle lost against the snow, the setting nine presses deep, the death that costs twenty minutes. A game with weak rules can survive a good interface. Good rules often can't survive a bad one, because nobody gets far enough to find them. These words let you point at the exact thing in the way.

HUDThe information laid over the picture of the game: health, ammo, score, map. The name comes from fighter planes, whose pilots read figures on the glass without looking down. Elements that exist only for the player, outside the world, are also called non-diegetic.
Diegetic UIInterface that exists inside the game's world, so the character could see it too: a meter on a suit, a map held in the hand. Fagerholt and Lorentzon's 2009 thesis Beyond the HUD names four kinds of game UI, sorted by two questions: is it in the story, and is it in the world's space?
Spatial UIInterface placed in the game's 3D space that the character can't see: an outline round an enemy, a glowing trail on the ground. It exists in the space but not in the story.
Meta UIInterface that stands for something in the story but is drawn on the screen rather than in the world: blood on the camera when you're hurt, a phone that fills the screen. It is in the story but not in the space.
Information hidingDeliberately leaving out a number the game knows, so the player has to read it from the world or work it out. In other words, deciding what the HUD should keep in the fog.
Text readabilityHow quickly and reliably someone can read what the interface is telling them while busy doing something else. For text it comes down to size, weight and contrast against whatever happens to be behind it.
UI scaleHow big the interface is drawn, and usually a setting that lets players change it. What matters is how large it looks from where they sit, which depends on the screen's size and their distance from it.
Safe areaThe part of the picture you can trust a screen to show. Many TVs blow the picture up slightly and crop its edges, which is called overscan, so anything important stays inside a margin. The broadcast standard keeps titles within the middle 90%.
Health barA shape that shows how much damage you can still take. A common refinement is the ghost bar: when you are hit, the chunk you lost stays visible in a paler colour for a moment, then drains away.
Damage numbersNumbers that jump off an enemy each time you hit it. They turn a hidden sum into feedback: how hard, and whether it was a critical hit.
MinimapA small map in a corner of the screen, showing what's nearby and where you are. It answers "where am I and where do I go?" without opening anything.
WaypointA marker that shows exactly where to go next, usually with a distance. It can sit on a compass, on the map or in the world.
Screen edge indicatorA mark at the edge of the screen pointing to something important that is off it, such as who just shot you or where your teammate is.
Quest logA screen that keeps track of what you've been asked to do and what you already know. It is the game's memory, so players don't need one of their own.
InventoryThe screen and the rules for what you're carrying. The rule is usually one of three: a set number of slots, a weight limit, or a grid in which each item has a shape.
TooltipA small box explaining the thing you are pointing at. A nested tooltip goes one further: words inside the box have tooltips of their own.
SignifierAny perceivable hint that an action is possible here: paint on a ledge, a glowing crack, a handle on a door. Don Norman brought the word into design to separate the thing you can do from the sign that tells you so.
Fitts's lawThe time it takes to reach a target grows with distance and shrinks with size, in a precise way. Paul Fitts measured it in 1954: time = a + b × log2(2D ÷ W), so doubling the distance or halving the width adds the same fixed amount.
Menu flowThe map of every screen in a game and how you get from one to the next: what Back does, where the cursor lands, what comes after a game over.
FrictionEverything that stands between wanting to do something and having done it: presses, waits, confirmations, screens. Some is deliberate, and most of it is an accident nobody noticed.
PauseStopping the game. It seems too obvious to need a word, except that many choices are hiding here: whether menus stop the world, what happens when the phone rings, and whether the game pauses itself when you lose focus.
Loading screenWhat the player sees while the game reads what it needs from the disc or drive. It can be a blank screen, a progress bar, a tip or even a bit of play.
OnboardingEverything that takes a stranger to being someone who knows how to play and wants to keep going. The start of that, the first few minutes, is often called the first-time user experience, or FTUE.
TutorialA part of the game set aside to explain how to play, usually with instructions. It can be a dedicated level, or short prompts that appear as they're needed.
Teaching by doingBuilding the level so the player works out a rule for themselves: first a safe place to try it, then a small test, then a real one. No text is needed.
Button promptThe on-screen icon that tells you which button to press. Glyphs are the icons themselves, and they have to match the device in your hands, because pads label the same positions differently.
Input remappingLetting players choose which button or key does what. Full remapping covers every action, including the menus.
SubtitlesDialogue as text on screen. Captions go further, with sounds and music as well. Done well, they come with a choice of size, a background, the name of whoever is speaking, and where that person is.
Colour-blind modesSettings that change a game's colours for people who see them differently, about 1 man in 12 and 1 woman in 200. The stronger rule goes with it: never let colour be the only thing that carries a meaning, and back it with shape, icon or position.
Accessibility optionsSettings that let more people play: for vision, hearing, movement and how fast you can think or react. The good ones change one specific barrier and leave the rest of the game as it is.
Motion settingsControls over how much the picture moves by itself: camera shake, head bob, motion blur, flashes, field of view. They are for people who get ill or disoriented from on-screen movement, and they should default to the system's reduced-motion setting where one exists.
One-handed playA way of playing with one hand, whether for someone who only has the use of one, or for a person holding a baby or a train strap. It usually means merging actions onto fewer buttons and letting the game do some of them for you.
Save systemThe rules for how your progress is kept: whether by save points, by saving anywhere, or by autosave, where the game writes your progress for you every so often. Each choice sets what a mistake or a crash can cost.
CheckpointA place in the level that you return to when you die, so you don't have to start over. Its spacing sets the price of every death.
QuicksaveOne button that saves right now, and another that takes you back. Save scumming is what people do with it: reloading again and again until the dice fall their way, or until they've got through without a scratch.
Attract modeWhat a game does when nobody is playing: shows itself. Arcade cabinets looped their title, scores and a demo that played itself, to pull people in from across the room. This site's home page is doing the same thing right now.