Super Smash Bros. Ultimate as a native Windows program, built on your own PC from your own copy of the game.

Setup guide · Playing · Multiplayer · DLC & unlocks · Game updates · Linux · macOS · How it works

• What is WindowSmash?
• What you need
• Install and play
• Controls
• Play with friends
• All guides
• Project status
• How it works
• Community
• Getting help
• For developers
• Legal

A Nintendo Switch and a Windows PC have different kinds of processors, so a Switch game can't run on a PC as it is. An emulator solves that by translating the game while you play. WindowSmash translates it once, ahead of time: it turns the game's code into C, compiles that into an ordinary Windows program, and adds a runtime that gives the game what it expects from a Switch: graphics, sound, controllers, files and networking.

The game itself still comes from your files. This repository holds only the translator (the recompiler) and the runtime.

What you get

• Up to eight controllers: Xbox, PlayStation, Switch Pro and most others, plus the keyboard.
• Windowed, borderless or full screen, always 16:9, with settings for G-Sync and FreeSync monitors.
• Online play through Local Wireless: rooms appear for every player in the online lobby, and nobody has to set up their router.
• The game's own Online mode, new and still being tested: Quickplay against WindowSmash's own game server.
• Your DLC fighters, and a tool that unlocks the base-game roster on your own save.
• Any game version, including 13.0.5 with Kazuya and Sora, and several versions side by side.
• An experimental Linux version, built from the same source: install-windowsmash.sh sets it up on Linux in one go (Linux).
• An experimental macOS version for Macs with Apple silicon, built from the same source: Install WindowSmash.command sets it up on the Mac in one go (macOS).

Install WindowSmash.bat does the setup for you. It installs the tools WindowSmash needs, finds your game files, and builds the game. Your part is to have your game files ready, start it, and choose a few things in one window. No programming knowledge is needed.

The whole journey at a glance:

Compare your PC with what you need above. (Settings → System → About shows the system type, the installed RAM and the processor.) The installer checks too: if your PC lacks something, such as a processor with AVX2 or enough free space, it stops and says what.

Played the game in yuzu or Ryujinx on this PC? Then your files are ready: the installer finds your keys, your firmware and the installed game, with its update and DLC, by itself.

Otherwise, put your files in three folders. The names are examples; any folders will do:

• Any game version should work. WindowSmash has been tested with 11.0.0 and 13.0.5. With an update file next to the game, the installer applies it for you. The game as first released (1.0.0) is the best base for an update. Without its update, though, the original release doesn't work yet: WindowSmash can't read its data.
• Compressed files (.nsz, .xcz) have to be turned back into .nsp or .xci first.
• Leave your game files where they are after the install: depending on their kind, the game keeps reading its data from them.

1. At the top of this page, click the green Code button, then Download ZIP.
2. Right-click WindowSmash-main.zip, choose Extract All…, pick a drive with about 60 GB free (for example C:\), and click Extract. You get a folder named WindowSmash-main; rename it to WindowSmash if you like.

1. Open the WindowSmash folder and double-click Install WindowSmash.bat.
2. Windows asks whether to run it (The publisher could not be verified): click Run. On some PCs a blue Windows protected your PC box comes instead: click More info, then Run anyway. Windows asks this once, about anything downloaded that isn't signed.

A window opens and shows each step as it goes. First it fetches the newest WindowSmash from GitHub, if there is a newer one, and checks your PC. Everything it shows is also kept in install.log in the WindowSmash folder.

The installer installs only what your PC is missing:

• Python, which runs WindowSmash's helper programs. If your PC has none, the installer puts a copy in the WindowSmash folder; nothing else on your PC changes.
• A compiler, which builds the game: LLVM's clang with Microsoft's C runtime and Windows SDK, downloaded into the WindowSmash folder (about 570 MB). Microsoft's parts come under Microsoft's license terms: the installer shows where to read them and asks whether you accept them; type yes and press Enter. If that download doesn't work, it installs the Visual Studio Build Tools instead, Microsoft's free tools: several gigabytes, with a progress window. Windows asks whether to allow the changes: click Yes. If it asks you to restart, do so, then double-click Install WindowSmash.bat again.
• SDL3, for PlayStation, Switch Pro and most other controllers.

Music and movies need nothing extra: their decoders come with WindowSmash and are built with the game.

When the tools are ready, the setup window opens:

Folders it found on your PC are filled in already; change any of them with Browse…. The line under each box says what is in the folder, for example the game's update: 13.0.5 and DLC: 99 add-on contents. Green means it's fine; red says what's missing.

Then:

• Type your online name, the name other players see.
• Leave the three boxes ticked, or untick what you don't want: a desktop shortcut, a Windows Firewall rule for playing online (Windows asks for permission once), and preparing the shaders after the build.
• Click Set up and build.

First it prepares your game files, which takes a few minutes: it decrypts the game if needed and applies your update (up to about 17 GB more space). Then it builds the game: your PC translates it into a Windows program, which takes 30 minutes to a few hours.

• A progress line shows how far the build has got and the time left. The time left appears once the first files are compiled, a few minutes in. The window's title shows it too, so you can follow it from the taskbar.
• You can keep using the PC, though it will be slower. Set it not to sleep while plugged in (Settings → System → Power) until the build is done.
• If the build stops (a restart, the PC going to sleep, an error you fixed), double-click Install WindowSmash.bat again: it carries on where it stopped.
• It's finished when the window says Done. Press a key to close it.

Double-click the Play SSBU shortcut on your desktop, or Play SSBU.bat in the WindowSmash folder.

• A small window called SSBU log opens minimized next to the game. Leave it: it closes with the game.
• If Windows Security asks whether to allow ssbu.exe on networks, allow it: it's needed for playing online.
• The first start takes a little longer. If you left preparing the shaders ticked, it runs in its own window at low priority; until it's done, some effects can stutter the first time they appear.

Then see the controls and how to play with friends below. The playing guide covers settings, saves and screenshots.

Double-click Install WindowSmash.bat again. It downloads the newest WindowSmash from GitHub if there is one, and builds again, which takes minutes rather than hours. Your game files, settings, save and online name stay as they are.

The installer stops with a message saying what went wrong and what to do; install.log keeps everything it showed. If something goes wrong in the setup guide lists the usual problems, and getting help says where to ask. Prefer to set it up yourself, step by step? The setup guide has every step by hand.

git clone https://github.com/SNO2207/WindowSmash.git
cd WindowSmash
& ".\Install WindowSmash.bat" -Game "D:\MyDump" -Keys "D:\MyKeys" -Firmware "D:\MyFirmware" -NoWizard

python tools/build_game.py --game "D:\MyDump" --keys "D:\MyKeys" --firmware "D:\MyFirmware"
& ".\Play SSBU.bat"

Plug in a controller and press a button: each pad becomes the next free player, up to eight. The keyboard plays as player 1.

Everyone needs the same game version, and each PC uses its own save. The multiplayer guide walks through each way and what to do when a room doesn't show up.

Looking for people to play with? Ask on the Discord server.

WindowSmash is experimental. Menus and matches run and Local Wireless connects, but much of it hasn't been tested widely yet.

There is no connection to Nintendo's online service, no claim of general Switch compatibility, and no verified performance target.

flowchart LR
    A[Your game's code] --> B[Recompiler: ARM64 and NEON to C]
    B --> C[Clang: Windows x64]
    C --> D[ssbu.exe on your PC]
    E[WindowSmash runtime] --> D
    F[Your game data and fonts] --> D
    D --> G[Direct3D 11, SDL3 and Windows]

The recompiler finds every function in the game's ARM64 code and writes it out as C. Clang compiles that C for Windows, and it is linked with the runtime, which stands in for the parts of the Switch the game talks to. The game's graphics commands go to Direct3D 11, its shaders are translated to HLSL, and its Local Wireless traffic travels over the internet through a relay.

The technical guide explains each part: the CPU model, function discovery, symbol binding, the services, the graphics path, shader compilation, the network protocol, save handling, and every tool in tools/.

Join the recomps.wtf Discord server to:

• get help with setting up and building;
• find people to play with online;
• share how the game runs on your PC;
• follow development and new releases.

When something goes wrong, first look at If something goes wrong in the setup guide. For a quick question, ask on Discord. To report a problem, open an issue and include:

• the game version, your Windows version, and your graphics card and driver version;
• which WindowSmash you have (the date you downloaded it, or the output of git rev-parse --short HEAD);
• what you did, what you expected, and what happened instead;
• after a crash or a freeze, the .txt report from the reports\ folder, and the end of build\play.log.

Run the source-only tests. They use made-up data, need no game files, and don't start the game:

python -m pip install -r tests/requirements-dev.txt
python -m unittest discover -s tests -v

The game-backed instruction and function tests are in the technical guide.

Everything generated or personal stays out of Git: build/, dump/, deps/, save/, version folders such as v13.0.5/, caches, captures, reports and local bundles.

No project-wide license has been chosen for the WindowSmash source yet; see the third-party notices for the parts that have their own. Super Smash Bros. Ultimate and related names belong to their respective owners. WindowSmash is an independent project and is not affiliated with or endorsed by Nintendo.