Paper prototypes

Why it matters

Building a digital game takes weeks before you can tell whether the idea is any good. A paper prototype can answer many of the same questions in an afternoon, for the price of some index cards. Studios use paper prototypes for board games, card systems, combat rules, economies, level layouts and even user-interface flows, because changing a rule with a pencil is far cheaper than changing code.

The core idea: prototype a question, not a game

A prototype is an experiment. Before you cut a single card, write down the one question it must answer:

• "Is choosing between attacking and defending interesting every turn?"
• "Does a shared resource make players negotiate?"
• "Can a player understand the map layout without explanation?"

Everything that does not help answer that question can be left out, faked or simplified. Art, story, menus and balancing details usually come later.

What you need

• Index cards or paper for cards, tiles and reference sheets
• Dice for randomness (a d6 gives 1-6; two d6 give a bell curve from 2 to 12)
• Tokens such as coins, buttons or beans for health, money or resources
• A pencil, so rules can change mid-game
• A timer or phone clock to measure turn length

Worked example: testing a light mechanic

Idea: a dungeon game where your torch is also your health. Question: is it tense to decide when to spend light?

1. Board: a 6 x 6 grid drawn on paper. Face-down cards in some squares are rooms.
2. Torch: each player starts with 10 coins (light).
3. Turn: move one square (costs 1 light). Flip a room card if you enter it.
4. Room cards: "+3 light (oil)", "monster: roll a d6, lose that much light", "treasure: 1 point", "dark room: lose 2 light".
5. End: when a player escapes from the exit square or runs out of light.

The first solo playthrough reveals that players can just walk straight to the exit and ignore treasure. The question is not answered yet: there is no tension because there is no temptation. One rule change: treasure is needed to unlock the exit. Now every step is a choice between safety and greed, and the second solo game feels very different.

That loop of build, play, notice, change one thing is the whole method.

Simulating digital games on paper

Paper works for digital ideas too:

• Real-time action: play in turns, where each turn is one second. You will learn about decision density, not reflexes.
• Hidden information: a friend acts as the "computer", hiding cards and applying rules.
• Level layouts: draw the level on graph paper and move a coin through it, counting steps and noting what the player can see.
• Interfaces: sketch each screen on a card and swap cards when a "button" is tapped.

Low fidelity on purpose

Rough materials send a useful message to testers: this can still change. Polished art makes people hesitant to criticise and makes you reluctant to throw things away. Keep it ugly until the rules work.

Common mistakes

• Prototyping everything at once. Too many systems means you cannot tell which one causes a problem.
• Spending hours on art. Words and arrows are enough.
• Never playing it yourself first. Solo play catches broken rules before you waste a tester's time.
• Changing many rules between tests. Change one or two things so you know what made the difference.
• Treating the prototype as the product. It exists to answer a question; once answered, it can be thrown away.

Quick recap

• A paper prototype is a cheap experiment that answers one design question.
• Use cards, dice, tokens and a pencil; leave out everything else.
• Build, play, notice, change one thing, and repeat.
• Digital ideas can be simulated on paper by turning time into turns and using a human "computer".

Try it

Open the Do tab and build a paper prototype around a single question.