Zelda II 2P Splitscreen — Android

Two players, one phone, one half of the screen each. An Android app that runs z2rs — a clean-room-style reconstruction of Zelda II: The Adventure of Link (NES) in Rust — with a portrait split screen: the picture is shown twice, the top copy upside down, and each player gets their own on-screen pad. The controls can be lifted off the screen edges, and the app remembers your ROM, so it boots straight into the game.

This fork publishes the Android build only. The desktop and browser builds come from the upstream project.

⬇ Download the latest APK · All releases and release notes · Everything about the app, players and hackers alike

What you get

• Mirrored two-player split screen. Tick Local co-op and the screen is cut in two, the top copy rotated 180°, each player holding one end of the phone. Orientation locks to portrait while the mode is on.
• Touch controls you can place. Two pads, mirroring each other, that can be moved away from the edges together (Pad ↑ / Pad ↓) or hidden altogether.
• Your ROM, remembered. Pick your own .nes once — it is hash-checked and stays on the device, and the app reloads it on every launch.
• HD graphics packs. Point the app at a pack folder and the art goes up to 4x; Use original art brings back the original graphics.
• Working sound, and the widescreen, save states, fast-forward, gamepad and online co-op features of z2rs are all still there.

Screenshots

Zelda II running in the Android app.

<img src="screenshots/screenshot-1.jpg" width="330" alt="Zelda II running in the Android app">	<img src="screenshots/screenshot-2.jpg" width="330" alt="Zelda II running in the Android app">
<img src="screenshots/screenshot-3.jpg" width="330" alt="Zelda II running in the Android app">	<img src="screenshots/screenshot-4.jpg" width="330" alt="Zelda II running in the Android app">

Install

1. Download z2rs-2p-splitscreen-0.1.0-debug.apk (866 KB) on your phone and open it. Android will ask you to allow installing from an unknown source.
2. Launch the app and, on the first run, pick your own Zelda II (USA) ROM when the Game ROM card asks for it.

Android 7.0 (API 24) or newer. From a computer:

adb install -r z2rs-2p-splitscreen-0.1.0-debug.apk

The APK is a debug build signed with the debug key, and it contains no ROM and no HD pack: bring both yourself.

f5d9e5f749f2ba782e72d90ce5f8def9e7c2b6ecc2599d1bf8b271cdf104d4ed  z2rs-2p-splitscreen-0.1.0-debug.apk  (SHA-256)

Two players on one phone

Tick Local co-op on the page. The screen becomes two copies of the game — the top one upside down — and a second pad appears above it, so both players read their half the right way up. ✕ 1 player, halfway down the right edge, takes you back to playing alone. If the pads sit awkwardly behind a case or a gesture bar, Pad ↑ and Pad ↓ in the Player card slide both of them out of the way at once; Hide touch pad removes them.

The same mode is in the desktop build, where it can be turned off with --split2p off.

Build the APK yourself

You need Rust stable with the wasm32-unknown-unknown target, wasm-pack, and a JDK (17) with the Android SDK.

# the web bundle must include the HD feature, or the HD card stays inert
RUSTUP_TOOLCHAIN=stable wasm-pack build crates/z2-web --target web --out-dir site/pkg --features hd

cd android
JAVA_HOME=/usr/lib/jvm/java-17-openjdk ./gradlew assembleDebug

The APK lands in android/app/build/outputs/apk/debug/. Nothing external is embedded unless you ask for it: Z2_APK_ROM=/path/to/dump and Z2_APK_HDPACK=/path/to/pack are the only ways in, and both stay out of the published APK. ANDROID.md has the details, and android/README.md covers the shell itself.

The upstream project (desktop and browser)

z2rs is a clean-room-style reconstruction of Zelda II: The Adventure of Link (NES) in Rust. It runs as a desktop app and in the browser (WebAssembly), and it is checked frame by frame against the original ROM running in a reference emulator.

You bring your own ROM. Nothing from the original game is distributed here. PROVENANCE.md records what reference material the project worked from and where every file in this repository came from, and LEGAL.md has the rules contributors follow.

On top of the original game, z2rs adds a few optional extras:

• widescreen, with real scenery in the margins instead of a stretched picture
• HD graphics packs, so you can repaint tiles and sprites at 2x to 8x
• two-player co-op with a second Link, on one machine or online
• save states, fast-forward, movie playback and gamepad support

Release announcement: Moddable Zelda 2 PC / Web port with Online Multiplayer Co-op and Widescreen Released. Chat is on Discord.

Play it on desktop

1. Download the archive for your system from the upstream releases page. There are builds for Linux, macOS (Intel and Apple Silicon) and Windows. Unpack it.
2. Start the launcher: z2rs-launcher.exe on Windows, z2rs.app on macOS, z2rs-launcher on Linux.
3. Pick your Zelda II (USA) ROM and press Play.

The launcher also sets the window size, fullscreen, widescreen (16:10, 16:9 or 21:9 ultrawide), an HD pack folder, and local or online co-op. Online co-op uses a public signalling server by default, so two players only need to agree on a room name.

Only one dump passes the check, identified by the hash of the ROM body with the 16-byte iNES header stripped: CRC32 BA322865, SHA1 11333adb723a5975e0ecca3aee8f4747aa8d2d26 (No-Intro USA). The file is only ever read in place — the Android app applies the same check.

Nothing in the archive is code signed. On macOS, right-click z2rs.app and choose Open the first time, or use Open Anyway in System Settings > Privacy & Security on newer versions. Windows SmartScreen wants More info and Run anyway, and on Linux the files may need chmod +x.

From a terminal you can skip the launcher:

./z2rs --rom /path/to/zelda2.nes --scale 3
./z2rs --fullscreen

z2-signal, the third binary in the archive, is the signalling server for online co-op. You only need it to host your own instead of using the public one.

Build the desktop and browser builds from source

You need Rust stable (cargo, rustc). The browser build also needs the wasm32-unknown-unknown target (rustup target add wasm32-unknown-unknown) and wasm-pack.

make build          # cargo build --workspace (no ROM needed)
make test           # cargo test --workspace (tests that need a ROM skip without Z2_ROM)
export Z2_ROM=/path/to/zelda2.nes
make run            # play the optimized desktop build
make run-web        # build the wasm bundle and serve it on :8080

make help lists every target. A target that needs Z2_ROM prints what to set and exits with status 2 when it is missing.

Controls

Action	Player 1	Player 2 (co-op)
A	Z	G
B	X	F
Start	Enter	T
Select	Shift (either one)	R
D-pad	arrow keys	W A S D

Tab fast-forward, F5 save state, F7 load state, F6 next save slot, P pause, . single-step while paused, F11 or Alt+Enter fullscreen, Esc leave fullscreen or quit. Gamepads work too.

Guides

Guide	What is in it
guide/desktop.md	the launcher, every key, save-state slots, command-line flags, the config file, gamepads
guide/browser.md	the web build, its URL parameters, optional features and bundle size
guide/co-op.md	two Links locally or online, widescreen, the portrait split, how they work and what they cannot do
guide/hd-packs.md	making a pack by painting over spritesheets of the game (make hd-sheets, make hd-pack) and playing with it
guide/development.md	repository layout, headless runs, and how the port is checked against the original

Contributing and legal

CONTRIBUTING.md covers setup, the pre-commit hook and the rules for tests that need a ROM. LEGAL.md explains what may never be committed. Read it before you open a pull request.

License

The z2rs source code is released under the MIT license (LICENSE). The license does not cover the original game, which you must supply yourself, nor the community or Patreon HD graphics packs, which are licensed for personal use and must not be redistributed.