Usagi

Features

Live reload. usagi dev watches your code and assets; saves apply without losing game state. Tweak a sprite in your editor and see it update instantly.
One-command export. usagi export packages your game for Linux, macOS, Windows, and the web.
Pause menu, free. Built-in pause menu with sfx and music volume, fullscreen toggle, and per-game keyboard + gamepad remapping.
Easy save data. One function to save and load your game state as a Lua table.
Small, fixed API. You can't do everything, but you've got what you need to make a great 2D game.
Constraints to inspire creativity. 320x180 default resolution, 16x16 default sprite grid, a single sprites.png for textures.

Bring your own sound effects, sprite editor, and music tools.

Getting Started

Bootstrap a project and start it in dev mode:

usagi init my_game
cd my_game
usagi dev

init writes main.lua (with _init / _update / _draw stubs), .luarc.json for Lua LSP support, .gitignore, meta/usagi.lua (API type stubs), and USAGI.md (a copy of these docs).

Edit main.lua, save, and the running game picks up the change without restarting or losing state. Drawing "Hello, Usagi!" looks like:

function _draw(_dt)
    gfx.clear(gfx.COLOR_BLACK)
    gfx.text("Hello, Usagi!", 10, 10, gfx.COLOR_WHITE)
end

Tags: gamedev lua

Last modified 21 June 2026

Usagi

Simple 2D Game Engine for Rapid Prototyping.

Features

Getting Started