Systems design in 12 slides

The short version. The long version is a career.

Start with the verb

A system is a thing the player does, not a thing the game has.

Bat. Build. Bluff. Hoard.

One loop, drawn badly

Draw the core loop on paper before the whiteboard, and on the whiteboard before the spreadsheet.

Bad drawings are honest. Good ones hide gaps.

Inputs the player controls

List every decision the player makes inside the loop.

If the list is one item long, it is a button, not a system.

Outputs the game wants

What does the rest of the game consume from this system? Currency, progress, story, a reason to come back tomorrow.

A system with no customer gets cut in the first budget review.

The shelf

Between earning and spending there is holding. How long, and why?

Design the waiting, not just the transaction.

Difficulty is a conversation

A difficulty curve is the game saying "I noticed you". Static curves stop noticing.

Dynamic difficulty needs a ceiling, a floor, and a reason to tell the player it moved.

Tunable from day one

Every number that matters lives in data, not in code, before the first playtest.

If a tuning change needs an engineer, it will happen half as often as it should.

Paper first, then one person

Playtest the system on paper with one person who has not heard the pitch.

The first thing they misunderstand is the design brief for the next week.

Write the hypothesis down

For every change: what you expect to move, when you will check, and what you will do if it does not.

The last line is the one that prevents permanent mistakes.

Mentoring is systems design

A team is a loop too. Inputs, outputs, a shelf where decisions wait.

Design the reviews the way you design the economy: short, frequent, and honest.

The only rule

Ship the smallest version that lets a player say the verb.

Then listen.