🕹️ A game about building emulators! Check it out!

Created by [r]labs.

• Full 🕹️ NEEES emulation guide from scratch
• Interactive 🔨 6502 Assembly tutorial
• Implement 🧠 CPU, 🖥️ PPU, and 🔊 APU in any order
• Play 👾 homebrew games to unlock ROMs
• 🧪 Unit tests, video tests, and audio tests are provided
• 💻 Unix-style shell and code editor
• 🎶 Original retro-synthwave soundtrack
• 📃 Included documentation and in-game dictionary
• 🗣️ Fully localized into English and Spanish
• 🐞 Powerful debugger with:
  • 🐏 Memory viewer
  • 🔢 Instruction log
  • 🏞️ Name tables, CHR, Sprites, Palettes
  • ♒ Individual APU channel views
  • 🎮 Controllers
  • 🗃️ Emulator logging
• 🔭 Free mode to use the IDE to develop emulators for other systems!

• Portable: .devz files (import/export from Settings menu)
• Web: IndexedDB and LocalStorage
• Steam/Windows: %USERPROFILE%/AppData/Roaming/EmuDevz
• Steam/Linux: $XDG_CONFIG_HOME/EmuDevz
• Steam/macOS: ~/Library/Application Support/EmuDevz

# install nvm & node
npm install
npm start

• Package levels: npm run package
• Sort locales: node scripts/sort-locales.js
• Sort dictionary entries: node scripts/sort-dictionary.js
• Build: npm run build
• Deploy to GitHub Pages: npm run deploy <GH_USERNAME> <GH_TOKEN>

cp pre-licenses.txt public/licenses.txt
yarn licenses generate-disclaimer --prod >> public/licenses.txt

These are notes from the January 2026 release on Steam. I hope these issues can be resolved in the future.

• On Windows 11, when using a full-screen Electron app with the Steam overlay, ghost Alt-Tab windows are created. As a workaround, fullscreen mode is disabled on Windows.

• The Steam overlay doesn't seem to work.

• The app doesn't boot in sandbox mode when launched via Steam. As a workaround, Steam launches the app with --no-sandbox.
• The app doesn't boot on Arch Linux with the latest Electron when using the Steam Linux Runtime 3.0. As a workaround, Electron 36.9.5 was used and forced to launch using X11 with --enable-features=UseOzonePlatform --ozone-platform=x11.