Gameplay (PlayState)
How play.PlayState is structured, what each helper owns, and the lifecycle of a song.
Charts & songs
The SwagSong/SwagSection chart format, loading, migration, events and weeks.
Characters & stages
The character JSON format, animation handling, stage JSON and hardcoded stages.
Options menu
The Option model, the category substates and how to add a new setting.
Shaders & effects
The shaders package, the Shader/Effect pair convention, runtime shaders and the script-facing API.
Editors
The in-game authoring tools — chart, character, dialogue, week, menu character and note splash editors.
Audio & music
Song audio, the freeplay music player, the sound tray, hitsounds and video playback.
Mobile
Touch controls, storage and permissions, the first-run copy state, and the Android platform services.
Debugging & crash handling
The FPS/memory overlay, crash handler and error state, Discord RPC and build metadata.
Deep links (phoenix://)
The custom URI scheme — routes, grammar, dispatch rules and per-platform registration.
Scripting runtime
How the Lua, Python and HScript hosts are implemented — registration, marshalling, hook dispatch and caching.