How to play retro games in your browser

Modern browsers ship with WebAssembly, an instruction set that runs at near-native speed. That's enough horsepower to emulate consoles up through the Game Boy Advance and Sega Saturn comfortably on a mid-range laptop, and even a phone handles 8-bit and 16-bit systems without breaking a sweat. There's no plugin to install, no Java, no Flash — the browser is the runtime.

The two engines that matter today are EmulatorJS (a fork of libretro cores ) and a handful of custom WebAssembly ports. Most browser-based retro game sites — including this one — wire one or both into a thin React or vanilla-JS shell, hand it a ROM file , and let the user play.

Browse the catalog by platform (NES, SNES, Genesis, GBA, etc.) or by category (action, RPG, puzzle, fighting). Most browser libraries include 1,000-3,000 titles spanning the cartridge era; ours has 2,074 at last count. Look for the platform badge on each card to confirm compatibility — anything labeled NES/SNES/GB/GBA/MD/MS/PCE will run smoothly on a phone, while N64/PS1/Saturn need a desktop browser to maintain 60 FPS.

Press the Play button on the game page. Three things happen behind the scenes: the emulator core (a 1-3 MB WebAssembly module) downloads, the ROM downloads from a public archive, and the audio context initializes. Total cold-start time is typically 5-15 seconds depending on ROM size and your connection. Once the emulator boots, save states and screenshot capture become available.

Default keyboard mappings:

• Arrow keys — D-pad / movement
• Z — A button (action / confirm)
• X — B button (cancel / secondary action)
• A / S — X / Y on systems with four face buttons
• Enter — Start
• Shift — Select
• F2 — Save state
• F4 — Load state

On mobile, on-screen touch controls overlay the screen automatically. For the best experience, plug a USB or Bluetooth controller into your computer or phone — most browsers expose the Gamepad API and the emulator picks it up automatically with no extra configuration.

• Use save states liberally — they’re free, and they’re the single biggest reason browser emulation feels better than the original hardware ever did.
• If audio glitches, lower your tab count. WebAssembly competes for the same audio worklet thread as other tabs.
• Fullscreen (F11 on most browsers) eliminates the window chrome and gives you the cleanest experience on a laptop.
• For longest battery life on a laptop, prefer 8-bit and 16-bit systems — they idle at <5% CPU.