ChampDiff • In development 2026

A game where friends race to guess League champions

A ChampDiff round on desktop: standings for two players, the guess box, and three guesses with green, gold and red clue cells.
Role
Product Design, UX Writing (EN, KO), Product Direction
Timeline
August 2026
Team
Solo
Tools
TypeScript, WebSockets, Redis, Vercel, Codex, Claude Code
Live
In development
Players racing in one room
10
Champions in the game
173
Languages, down to the champion search
2

ChampDiff is a champion guessing race for friends who play League of Legends. Up to ten people hunt the same hidden champion in one room. Each wrong guess gives clues only you can see.

I designed it and made every product call. AI agents wrote the code, and I reviewed it.

Problem

Rivals need to feel close without helping each other.

In a solo puzzle, your clues are the whole game. In a race, they're also a leak. If you can see a friend's clues, you can copy them. So rivals had to feel close without helping.

The ChampDiff home screen: a name field, a create room button, a join by code field and a sample clue readout for Ahri.
The first screen and a real clue row.

Process

Rivals see your attempts and score, never your clues.

I split what you know from what rivals see. Your clue rows stay private. Everyone else sees your attempts and score. The server owns the answer. Pressure comes from knowing someone is close, not from knowing what they know.

Standings for two players, each showing round wins and guesses used, with no clue rows.
Rivals see round wins and guesses used. Their clue rows stay on their own screen.

Process

I show all ten seats on a phone, not just four.

To save space, I first showed only three open seats. Hosts read that as a four-person room. So I reversed it. All ten seats now show as small tiles.

A phone lobby with two joined players and eight numbered open seats, three across.
All ten seats on a phone, so no host reads the room as full at four.

Reflection

It runs for my friends while Riot reviews it.

It only goes public if Riot's review says yes. I built the game first and asked later. Next time, I'd talk to the rights holder in week one.

For now, it runs for my friends and me.