Kaiju Engine is a full-featured 2D/3D game engine written in Go, backed by Vulkan for rendering. It includes a built-in editor that runs as a game within the engine, providing workspaces for stage management, shader design, render graph editing, terrain painting, and content browsing. The engine core handles entity management, physics (custom Graviton engine with rigid bodies, constraints, and collision detection), audio (SoLoud via CGo), networking (UDP with reliability), UI (custom HTML/CSS markup engine with flexbox/grid layout), asset pipeline (glTF, FBX, textures, fonts), and cross-platform support (Windows, Linux, macOS, Android). The editor adds undo/redo history, action system with key bindings, Lua scripting, a Web API, and a plugin system. The codebase is a monorepo with heavy use of Go build tags for platform-specific code and feature flags.