REAL-TIME

A build · Multiplayer game

I Call On.

A fast-paced party game that tests how quickly you can think under pressure, built around real-time synchronisation, fairness, and repeat play.

Overview

A simple concept with a hard system underneath.

I Call On is a real-time multiplayer naming game for friends and families. The caller picks a letter; everyone else races to name an animal, a place, or a person starting with that letter, before the caller stops the round. Score points for valid answers, move through the categories, and see who pulls ahead.

What makes the game work isn't the concept; it's the execution. The experience depends entirely on speed, synchronisation, and fairness across every player in real time. When the round ends, it has to end for everyone, instantly. A half-second delay breaks the whole thing.

TypeA GrayTop build

FocusGame design · UX · Frontend · Real-time logic

Stack

React Native Custom game logic Real-time sync

SYNCHRONISE

The challenge

Making real-time gameplay feel fair and instant

"Even small delays break the experience."

The core challenge wasn't the game idea; it was the system behaviour. When the caller ends a round, all players must stop instantly. Inputs from multiple users have to be captured and scored fairly. Network delays can create inconsistencies between players: one phone still accepting answers while another has already locked.

Without tight synchronisation, the game quickly feels unreliable, and a party game that feels unreliable doesn't get played twice. The architecture had to deliver near-instant state updates across every connected device, regardless of network conditions.

What I built

The system behind the game.

sync_alt

Synchronised round control

The caller controls the round lifecycle, and every player device stays in sync when rounds start and stop. When the caller presses stop, every phone stops, simultaneously, across variable mobile connections.

keyboard

Real-time input handling

Players submit answers at the same time, with logic to capture, validate, and score responses inside the time window, keeping it fair regardless of who answers first or how fast their connection is.

groups

Caller / player role system

Distinct flows for the caller, who controls round pacing, and players, who compete to answer. Each role gets a different interface, keeping the dynamic clear without needing a tutorial.

emoji_events

Lightweight scoring engine

Points awarded on valid entries across categories, with a game loop kept intentionally lean: fast rounds, minimal friction, high replayability. Easy to start, difficult to put down.

System insight

I Call On is a timing-sensitive system.

Simple concept + complex synchronisation requirement

Variable network conditions → consistent, fair experience for all players

Caller stops the round → everyone stops, simultaneously

Even with a simple concept, the complexity lives in making the experience feel instant and fair for everyone in the room. That's the part worth building well, and the part off-the-shelf tooling never quite gets right.

More work

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