SubsurfEmpire

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  multiplayer

Inspiration

The inspiration came from the classic io-style games like Paper.io and Agar.io — tried and tested formulas that are simple to understand, competitive, and endlessly replayable. I wanted to bring that same addictive energy into the Reddit ecosystem using Devvit, while making it more dynamic and community-driven.

What it does

SubsurfEmpire is a synchronized multiplayer territory-claiming game where players compete in real-time to expand their zones, cut off opponents, and dominate the board. The gameplay is fast, strategic, and persistent — everything updates live through Redis, allowing multiple players to interact seamlessly.

How we built it

The game is built using PhaserJS for the 2D rendering and physics, while Redis handles the real-time multiplayer synchronization. Devvit powers the Reddit integration layer — managing user sessions, storing game data, and connecting players through Reddit’s community features. To optimize performance, player movements are transmitted as directional inputs only, with each client predicting positions locally for smooth real-time gameplay.

Challenges we ran into

The biggest challenge was achieving reliable real-time multiplayer communication without exceeding Redis channel limits. Balancing update frequency, player sync, and smooth gameplay required a lot of iteration and tuning.

Accomplishments that we're proud of

The biggest accomplishment is getting multiplayer to work efficiently by sending only direction data on input events and predicting all other players’ positions on the client side — achieving real-time gameplay with minimal bandwidth and latency.

What we learned

Building real-time multiplayer systems requires more than just sending position data — it’s about optimizing communication, prediction, and reconciliation. I also learned how to use Devvit and Redis effectively to create responsive, multiplayer experiences within Reddit’s environment.

What's next for SubsurfEmpire

Next, I plan to:

• Add AI-powered bots to fill lobbies and make the experience more engaging.
• Introduce custom trails and skins to let players personalize their territory style.
• Explore monetization options to sustain and scale the game.

Built With

• devvit
• javascript
• node.js
• phaser.js
• redis