Cleo Selene

What it does

Cleo Selene is a multiplayer-first, server-rendered game engine that uses Lua scripting. All game logic runs on the server, and clients receive only drawing primitives via WebRTC or WebSocket. This eliminates the need for client-side code and prevents cheating, as the client has no knowledge of the game state.

Who it is for

Cleo Selene is designed for game developers who want to build multiplayer games without the complexity of client-server synchronization. It is particularly suited for indie developers, hobbyists, and small teams who prefer Lua scripting and want to deploy on their own infrastructure. The engine is free for personal or commercial use, with no per-player fees.

Why it matters

Traditional multiplayer game development requires careful state management, lag compensation, and anti-cheat measures. Cleo Selene simplifies this by rendering everything server-side, streaming only drawing commands to clients. This approach offers sub-frame latency via WebRTC, native performance for physics and pathfinding (written in Rust), and inherent cheat protection. Additionally, the engine is open source and supports AI-native debugging via an MCP endpoint, allowing LLMs to inspect game state in real-time.

Launch signal

Cleo Selene was launched on Hacker News as a Show HN post titled "Server-rendered multiplayer games with Lua (no client code)". The website provides a playable demo (Astro Maze), a CLI installer for macOS and Linux, and full API documentation. The engine is in early stages, with Windows support planned but not yet available.

Brand and naming

The name "Cleo Selene" combines "Cleo" (short for Cleopatra or clarity) with "Selene" (Greek goddess of the moon), evoking a sense of elegance and celestial guidance. The branding emphasizes simplicity and security, with a tagline that clearly states its unique value proposition: server-rendered multiplayer with no client code. The logo is a simple geometric design, reinforcing the clean, developer-focused aesthetic.