Analyse why games work, build and playtest paper prototypes, balance systems and levels, and communicate a design with a one-page GDD and a pitch.

Game Design Fundamentals

## Why it matters

Almost every game has an **economy**: something players earn, spend and want more of. It might be gold, health, ammunition, time, cards in hand or experience points. If resources flow in too fast, choices stop mattering and players get bored. Too slow, and they feel stuck. **Balance** is the work of tuning those flows (and the strength of options) so that choices stay interesting.

## The core idea: sources, sinks and stocks

Think of each resource as water in a tank.

- **Sources (faucets)** add to it: quest rewards, income per turn, enemies dropping coins.
- **Sinks (drains)** remove it: buying items, upkeep, repair costs, death penalties.
- **The stock** is how much the player has right now.

The **net flow** per turn is sources minus sinks. If the net flow is always positive, the stock grows without limit and prices become meaningless (inflation). If it is always negative, players run dry. Designers aim for a net flow that lets players afford meaningful things at a pace that matches the game's length.

```text
gold_next_turn = gold_now + income - upkeep
```

## Worked example: how long until the castle?

A player starts with 20 gold, earns 12 per turn and pays 4 upkeep. A castle costs 100.

- Net flow = 12 - 4 = 8 gold per turn.
- Gold needed = 100 - 20 = 80.
- Turns = 80 / 8 = **10 turns**.

If playtests show 10 turns is too long, you can raise income, cut upkeep, lower the price, or add a one-off source (a quest reward). Each lever has side effects: raising income also speeds up every other purchase. That is why designers prefer to change **one number at a time** and re-check.

## Types of balance

- **Economic balance:** the flow of resources over time (the example above).
- **Option balance:** no single strategy, weapon or character is the obvious best choice. Rock-paper-scissors is perfectly balanced because each option beats one and loses to one.
- **Difficulty balance:** challenge matches player skill (covered in the next lesson).
- **Fairness between players:** for example, first-player advantage in turn-based games.

Perfect balance is not always the goal. Some imbalance creates interest: a strong but risky option, or a character that is great on one map. What matters is that every option has a **reason to be chosen**.

## Using spreadsheets and simulations

Designers model economies in spreadsheets or small scripts before touching the game. A simple simulation answers questions like "after 30 turns, how much gold does a careful player have?" or "can a player ever get stuck with zero gold and no way to earn more?". That last one, a **dead state**, is one of the worst balance bugs, and simulation catches it early.

Pure functions (same inputs, same outputs, no side effects) are ideal for this: you can call them with hundreds of combinations and compare the results.

## Common mistakes

- **Tuning by feel only.** Write down the numbers and model them; intuition about growth curves is often wrong.
- **Forgetting sinks.** Many games add more and more rewards and end with players hoarding resources that have nothing to buy.
- **Changing many numbers at once.** You lose track of what caused the change.
- **Dead states.** Make sure a player at zero can always earn their way back.
- **Balancing only for experts or only for beginners.** Test both a careless and a careful strategy.

## Quick recap

- Economies are sources, sinks and stocks; the net flow sets the pace.
- Turns to afford something = (price - current) / net flow, rounded up.
- Balance covers economies, options, difficulty and fairness; some imbalance is healthy.
- Model with small pure functions or spreadsheets, change one number at a time, and watch for dead states.

## Try it

Open the Do tab and write the two economy functions a designer would use to tune the castle example.


Model a game's resource economy with sources and sinks, and tune it with a small simulation.

Balance and economies

How Video Game Economies are Designed

Perfect Imbalance - Why Unbalanced Design Creates Balanced Play - Extra Credits

Choose one mechanic for the level to teach, such as a double jump, a moving platform or a key that opens a door.

Draw the level as a side or top view on graph paper, divided into four sections: introduce, practise, twist, test.

In the introduce section, present the mechanic where failure is safe (a short fall, an instant retry).

In the practise and twist sections, raise difficulty one step at a time and add one new combination or complication.

In the test section, combine everything once with real stakes. Add a rest moment just before it.

Sketch the difficulty curve under the map: x is position in the level, y is difficulty from 1 to 5. Check that it rises with small dips for rest.

Play it on paper with a coin as the player and count the steps per section. Ask a friend to 'play' it by tracing with a finger and say where they think they would die.

## Why it matters

A level is where mechanics meet the player. The same jump can feel trivial, thrilling or unfair depending on where it is placed, what comes before it and what happens if you miss. **Level design** is the craft of arranging space, challenges and information so players learn, feel challenged and keep moving forward.

## The core idea: teach, then test

Many great levels follow a pattern often described as **introduce, develop, twist, conclude**:

1. **Introduce** the mechanic where failure is safe. The first gap is over solid ground, not a pit.
2. **Develop:** use it a few times with rising difficulty so the player builds confidence.
3. **Twist:** combine it with something else or change the context (a moving platform, a timer).
4. **Conclude:** a final test that uses everything, followed by a reward.

This is how many games teach without text: the level design itself is the tutorial.

## Difficulty curves

A **difficulty curve** plots challenge against time or position in a level or game. A straight line upward exhausts players; a flat line bores them. Good curves rise overall with **rhythm**: tension, then release.

```text
difficulty
 5 |                         /\
 4 |              /\        /  \
 3 |       /\    /  \  /\  /
 2 |  /\  /  \  /    \/  \/
 1 | /  \/    \/
   +--------------------------------> position
     intro   practise   twist   test
```

Rest moments (a safe room, a cutscene, an easy collectable) let tension drop so the next peak feels big. Psychologist Mihaly Csikszentmihalyi's idea of **flow** describes the goal: challenge just above the player's current skill, rising as their skill rises.

## Guiding the player

Levels also communicate where to go:

- **Landmarks:** a tall tower or bright light visible from far away gives a goal.
- **Lighting and colour:** players move toward light and toward contrasting colours.
- **Leading lines:** paths, rails, cables and edges point the way.
- **Gating:** a locked door seen early creates a goal; the key found later gives satisfaction.
- **Breadcrumbs:** collectables placed along the intended route.

## Worked example: a double-jump level

Mechanic to teach: the double jump.

| Section | Design | Difficulty |
|---|---|---|
| Introduce | a ledge too high for one jump; falling just lands you back at the start | 1 |
| Practise | three gaps, each slightly wider; the last needs good timing | 2-3 |
| Rest | a safe platform with a few coins | 1 |
| Twist | double jump onto a moving platform; missing drops you one screen back | 4 |
| Test | a sequence of all of the above over a pit, with a checkpoint just before it | 5 |
| Reward | an exit with a view of the next area | - |

Notice that the **cost of failure** rises with skill: early mistakes are free, the final test has stakes but a nearby checkpoint keeps it fair.

## Blockouts

Professional level designers build **blockouts** (also called greyboxes): the level made from plain shapes with no art. Paper sketches and grey boxes let you test layout, pacing and sightlines cheaply, just like a paper prototype tests rules.

## Common mistakes

- **Teaching and testing at the same time.** If the first use of a mechanic can kill the player, they learn to fear it, not use it.
- **Unfair failures.** Hazards the player could not see coming feel cheap. Show danger before it matters.
- **No rest.** Constant peak difficulty is exhausting and flattens the curve.
- **Designing for your own skill.** You have played the level a hundred times. New players have not; playtest it.
- **Long walks back after failure.** Place checkpoints so retries are fast.

## Quick recap

- Introduce a mechanic safely, develop it, twist it, then test it.
- Difficulty curves rise overall with rhythm: peaks and rests.
- Guide players with landmarks, light, lines, gates and breadcrumbs.
- Block out levels cheaply first and playtest with fresh players.

## Try it

Open the Do tab and design a level on graph paper with its difficulty curve.


Design a level that teaches a mechanic and raises difficulty along a deliberate curve.

Level design

5 Tips for Great Level Design

Difficulty Curves

Write a logline: one sentence with a character, a goal, an obstacle and the stakes.

Describe the world in three sentences: where, when, and the one rule that makes it different from ours.

Write a short profile of the player character: what they want, what they fear, and why the player should care.

List the three main story beats (beginning, turning point, ending), one or two lines each.

Connect story to mechanics: for each core mechanic, write one sentence on how it fits the world (for example, 'light is health because the cave spirits feed on darkness').

Note two places where the environment tells story without text (a ruined camp, a child's drawing on a wall).

Read the brief aloud in under two minutes. Cut anything that does not affect what the player does or feels.

## Why it matters

Story and world give players reasons to care: about a character, a place, a choice. But games are not films. Players act, and the story has to survive their choices, their skipping of dialogue and their wandering off to collect mushrooms. **Narrative design** is the craft of telling stories through play, and **worldbuilding** is creating a setting consistent enough that players can believe in it and act within it.

## Narrative designer vs writer

In studios these roles often overlap but are different:

- A **writer** writes the words: dialogue, item descriptions, barks.
- A **narrative designer** decides how story is delivered through systems, levels and choices, and makes sure story and mechanics support each other.

Small teams often combine both, and game designers on any team benefit from narrative thinking.

## The core idea: story through play

Games tell stories in several layers:

| Layer | What it is | Example |
|---|---|---|
| **Embedded narrative** | authored story the designer wrote | cutscenes, dialogue, quests |
| **Environmental storytelling** | story told by the space itself | a barricaded door and claw marks tell you something happened |
| **Emergent narrative** | stories that arise from systems and player actions | the time your last unit survived against the odds in a strategy game |
| **Lore** | background history, often optional | books, item descriptions, codex entries |

Strong games use several layers, so players who skip dialogue still understand the world through what they see and do.

## Ludonarrative harmony

When mechanics and story agree, they reinforce each other. When they clash, players feel it. A character described as gentle who mows down hundreds of enemies is a classic example of **ludonarrative dissonance**. You do not have to solve this perfectly, but asking "what does this mechanic say about the character and world?" makes designs more coherent.

## Worldbuilding that serves play

A believable world is consistent, not exhaustive. Focus on:

- **The core difference:** the one thing that makes this world unlike ours (magic is fuelled by memory; the sun never sets).
- **Rules and consequences:** if magic costs memories, characters who use it a lot should forget things.
- **Factions and conflict:** groups that want different things create quests and choices.
- **Visible history:** ruins, signs and changes in architecture show the past without a lecture.

Every element should eventually touch play: a place to explore, a choice to make, a mechanic it explains.

## Worked example: a narrative brief

For the dungeon game from the paper prototype lesson:

- **Logline:** A lamplighter's apprentice must descend into the flooded mines to relight the beacon before the village's last oil runs out.
- **World:** a mining village where the darkness below is alive and drinks light; oil is the most valuable thing anyone owns.
- **Character:** Mara, 15, wants to prove she is not a child; fears the dark that took her mentor.
- **Beats:** she enters the mines; she finds her mentor's lamp still burning deep below (turning point); she must choose to carry it home or use its oil to relight the beacon.
- **Mechanics fit:** light is health because the darkness drinks it; treasure is needed for the exit because the miners' tokens open the lift.
- **Environmental story:** abandoned lamps placed further and further apart; scratched tally marks on walls.

That one page gives artists, writers and level designers a shared direction.

## Common mistakes

- **Lore dumps.** Long text at the start before players care. Reveal the world as they explore it.
- **Story that ignores play.** If cutscenes say one thing and mechanics another, players believe the mechanics.
- **Too much worldbuilding, too little game.** A 50-page history no one sees does not help the player.
- **Forcing a single path in a game about freedom.** Match narrative structure (linear, branching, emergent) to the game.

## Quick recap

- Narrative design tells story through play; worldbuilding creates a consistent setting to act in.
- Use embedded, environmental, emergent and lore layers together.
- Aim for mechanics and story that agree (ludonarrative harmony).
- A one-page narrative brief aligns the team: logline, world, character, beats and how mechanics fit.

## Try it

Open the Do tab and write a one-page narrative brief for your game.


Write a one-page narrative brief that ties story, world and mechanics together.

Narrative and worldbuilding

The Three Pillars of Game Writing - Plot, Character, Lore - Extra Credits

How Level Design Can Tell a Story

Tune a resource economy, design a level with a difficulty curve, and write a one-page narrative brief.