A powerful multi-system emulator for Windows, Linux, and macOS
High-accuracy emulation • TAS editing • Advanced debugging • Pansy metadata export
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Nexen is a multi-system emulator based on Nexen2 with significant enhancements: a full-featured TAS editor with undo/redo and greenzone support, an infinite save state system with visual picker, a ZIP-based movie format with multi-format import/export, 🌼 Pansy metadata export for integration with the Flower Toolchain disassembly pipeline, and active development of Sega Genesis, Atari 2600, and Fairchild Channel F support.
Download pre-built binaries from the Releases page.
| Build | Download | Notes |
|---|---|---|
| Standard | Nexen-Windows-x64-v1.4.43.exe | Single-file, recommended |
| Native AOT | Nexen-Windows-x64-AoT-v1.4.43.exe | Faster startup |
| Build | Download | Notes |
|---|---|---|
| AppImage x64 | Nexen-Linux-x64-v1.4.43.AppImage | Recommended |
| AppImage ARM64 | Nexen-Linux-ARM64-v1.4.43.AppImage | Raspberry Pi, etc. |
| Binary x64 (clang) | Nexen-Linux-x64-v1.4.43.tar.gz | Tarball, requires SDL2 |
| Binary x64 (gcc) | Nexen-Linux-x64-gcc-v1.4.43.tar.gz | Tarball, requires SDL2 |
| Binary ARM64 (clang) | Nexen-Linux-ARM64-v1.4.43.tar.gz | Tarball, requires SDL2 |
| Binary ARM64 (gcc) | Nexen-Linux-ARM64-gcc-v1.4.43.tar.gz | Tarball, requires SDL2 |
| Native AOT x64 | Nexen-Linux-x64-AoT-v1.4.43.tar.gz | Faster startup |
| Build | Download | Notes |
|---|---|---|
| Standard | Nexen-macOS-ARM64-v1.4.43.zip | App bundle |
| Temporarily unavailable | .NET 10 ILC compiler bug |
Notes:
- Linux requires SDL2 (
sudo apt install libsdl2-2.0-0)- macOS: Right-click → Open on first launch to bypass Gatekeeper
- macOS Intel (x64) builds are no longer provided
- macOS Native AOT is disabled due to a .NET 10 ILC compiler crash
| System | CPU | Status |
|---|---|---|
| NES / Famicom | MOS 6502 | ✅ Full |
| SNES / Super Famicom | WDC 65816 | ✅ Full |
| Game Boy / Game Boy Color | Sharp LR35902 | ✅ Full |
| Game Boy Advance | ARM7TDMI | ✅ Full |
| Sega Master System / Game Gear | Zilog Z80 | ✅ Full |
| Sega Genesis / Mega Drive | Motorola 68000 | 🔄 In Progress |
| PC Engine / TurboGrafx-16 | HuC6280 | ✅ Full |
| WonderSwan / WonderSwan Color | NEC V30MZ | ✅ Full |
| Atari 2600 | MOS 6507 | 🔄 In Progress |
| Atari Lynx | WDC 65SC02 | ✅ Full |
| Fairchild Channel F | Fairchild F8 | 🔄 In Progress |
- High-accuracy cycle-accurate CPU and PPU emulation across all systems
- Full coprocessor support (Super FX, SA-1, DSP, Cx4, SDD-1, OBC-1, S-RTC, BS-X)
- Comprehensive mapper and memory controller support
- Netplay multiplayer with rollback
| Feature | Description |
|---|---|
| Infinite Saves | Unlimited timestamped saves per game |
| Visual Picker | Grid view with screenshots and timestamps (Shift+F1) |
| Quick Save | F1 to save, Shift+F1 to browse |
| Designated Slots | 3 dedicated slots (F2/F3/F4 load, Shift+F2/F3/F4 save) |
| Recent Play | 36 rolling checkpoints at 5-minute cadence (about 3 hours) |
| Auto-Save Log | Periodic timestamped progress entries (no overwrite) |
| Per-Game | Saves organized by ROM hash |
- Nexen Movie Format (.nexen-movie) — ZIP-based with JSON metadata, input log, savestate, and SRAM
- Recording & Playback — Frame-by-frame with rerecording support
- Multi-Format Import/Export — BK2 (BizHawk), FM2 (FCEUX), SMV (Snes9x), LSMV (lsnes), VBM (VBA), GMV (Gens)
- Multi-System TAS — Full TAS support for all emulated systems including Channel F
- Piano Roll — Visual timeline for frame-by-frame editing with batch paint
- Full Undo/Redo — Every operation (toggle, paint, insert, delete, clear, fork) is undoable
- Greenzone — Instant seeking with automatic savestates
- Input Recording — Capture, insert, and overwrite modes
- Branches — Fork, compare, and load alternate strategies
- Lua Scripting — Automate TAS workflows with full undo integration
| Tool | Description |
|---|---|
| Disassembler | Full CPU disassembly with labels and navigation |
| Memory Viewer | Hex editor with search and watch |
| Breakpoints | Execution, read, and write breakpoints |
| Trace Logger | CPU execution logging with filtering |
| Code/Data Logger | Track ROM coverage (CDL) |
| Profiler | Callstack-based CPU profiling |
| 🌼 Pansy Export | Export symbols, CDL, cross-refs, and source maps to universal metadata format |
- Multiple shader and filter options (NTSC, PAL, HQ2x, etc.)
- Integer scaling and aspect ratio correction
- Per-channel volume control
- HUD overlays for debugging
- Audio and video recording
- Download Nexen-Windows-x64-v1.4.43.exe
- Run the executable (no installation needed)
- File → Open to load a ROM
- Download Nexen-Linux-x64-v1.4.43.AppImage
chmod +x Nexen-Linux-x64-v1.4.43.AppImage./Nexen-Linux-x64-v1.4.43.AppImage
For non-AppImage builds, install SDL2 first:
sudo apt install libsdl2-2.0-0
- Download Nexen-macOS-ARM64-v1.4.43.zip
- Extract and move
Nexen.appto Applications - Right-click → Open (first launch only, to bypass Gatekeeper)
| Guide | Description |
|---|---|
| Save States Guide | Quick save, designated slots, and visual picker workflows |
| Rewind Guide | Rewind usage and route iteration workflows |
| Movie System Guide | Record, playback, import/export, and deterministic playback |
| TAS Editor Manual | Complete frame-by-frame TAS editing workflow |
| Debugging Guide | Disassembler, memory viewer, breakpoints, trace, and CDL |
| Video and Audio Guide | Rendering and audio configuration |
| Shortcut | Action |
|---|---|
| F1 | Quick Save (Timestamped) |
| Shift+F1 | Browse Save States |
| F2/F3/F4 | Load Designated Slots 1-3 |
| Shift+F2/F3/F4 | Save Designated Slots 1-3 |
| Ctrl+S | Quick Save (Alt) |
| Ctrl+Shift+S | Save State to File |
| Ctrl+L | Load State from File |
| Escape | Pause/Resume |
| Tab | Fast Forward |
| Backspace | Rewind |
| F11 | Toggle Fullscreen |
| F12 | Screenshot |
| Shortcut | Action |
|---|---|
| Escape | Pause/Resume Playback |
| ` (backtick) | Frame Advance |
| Backspace | Frame Rewind |
| Insert | Insert Frame |
| Delete | Delete Frame |
| Ctrl+Z | Undo |
| Ctrl+Y | Redo |
| Ctrl+G | Go to Frame |
| Ctrl+B | Create Branch |
Nexen is the play & debug stage of the Flower Toolchain — an integrated pipeline for playing, debugging, disassembling, editing, and rebuilding retro games:
🎮 Play & Debug (Nexen) → 🌺 Disassemble (Peony) → ✏️ Edit (Pansy UI) → 🌸 Build (Poppy) → ✅ Verify (Game Garden)
| Stage | Tool | Purpose |
|---|---|---|
| 1. Play & Debug | Nexen | Run games, export CDL + symbols + source maps via 🌼 Pansy |
| 2. Disassemble | 🌺 Peony | ROM → annotated .pasm source code |
| 3. Edit & Document | 🌼 Pansy UI | View and edit disassembly metadata |
| 4. Build | 🌸 Poppy | .pasm source → ROM |
| 5. Verify | 🌱 Game Garden | Roundtrip byte-identical rebuild verification |
| Document | Description |
|---|---|
| Documentation Index | Entry point for all user-facing docs |
| Manual Testing Hub | Ranked manual release validation workflows |
| Compiling | Build from source |
| SteamOS / Steam Deck | Running Nexen on SteamOS and Game Mode |
| Performance Guide | Performance strategy and references |
| Theme Customization Guide | Theme tokens, runtime mapping, and safe update workflow |
| Archive Stack | ZIP/7z read-write support matrix and packaging behavior |
| Third-Party Source Policy | Package-first dependency policy and CI guardrails for vendored source |
| Third-Party Source Inventory | Current measured vendored source footprint and caps |
| Release Guide | Creating releases |
| Changelog | Version history |
| System | Guide |
|---|---|
| All Systems | Systems Index |
| NES / Famicom | NES Guide |
| SNES / Super Famicom | SNES Guide |
| Game Boy / GBC | GB Guide |
| Game Boy Advance | GBA Guide |
| Sega Master System / GG | SMS Guide |
| Sega Genesis / Mega Drive | Coming soon |
| PC Engine / TG-16 | PCE Guide |
| WonderSwan / WSC | WS Guide |
| Atari 2600 | Coming soon |
| Atari Lynx | Lynx Guide |
| Fairchild Channel F | Channel F Guide |
| Document | Description |
|---|---|
| Architecture Overview | System design |
| C++ Development Guide | Coding standards |
| Developer Tasks | What to work on next |
| Code Documentation Style | C++ documentation style guide |
| Build and Run | Building and running Nexen |
| Profiling Guide | Performance profiling |
| ASan Guide | AddressSanitizer configuration |
| Movie & TAS Subsystem | Movie recording and TAS internals |
| TAS Algorithm Reference | TAS data structure and undo system design |
| Audio Subsystem | Audio processing and resampling |
| Video Rendering | Video rendering pipeline |
| Input Subsystem | Input and controller handling |
| Debugger Subsystem | Debugger internals |
| Utilities Library | Shared utility library |
| Pansy Integration | Metadata export system |
| Channel F Master Plan | Fairchild Channel F roadmap |
| Channel F Implementation Prompts | Ordered multi-session execution prompt pack |
| Channel F Source Index | External references mapped to implementation work |
| Document | Description |
|---|---|
| NES Core | NES/Famicom emulation core |
| SNES Core | SNES/Super Famicom emulation core |
| GB/GBA Core | Game Boy and GBA emulation core |
| SMS/PCE/WS Core | SMS, PCE, and WS core |
| Lynx Core | Atari Lynx core |
| Component | Version | Notes |
|---|---|---|
| C++ Compiler | C++23 (MSVC v145+, Clang 18+, GCC 13+) | /std:c++latest |
| .NET SDK | 10.0+ | Download |
| SDL2 | 2.0+ | Linux/macOS only |
Nexen resolves Pansy.Core from NuGet; you do not need a sibling pansy repo checked out next to Nexen.
- Install Visual Studio 2026 with "Desktop development with C++" workload
- Install .NET 10 SDK
- Open
Nexen.slnand build Release x64
# Install dependencies (Ubuntu/Debian)
sudo apt install build-essential clang-18 libc++-18-dev libsdl2-dev
# Build
make -j$(nproc)
dotnet publish -c Release UI/UI.csprojSee COMPILING.md for detailed instructions.
Use these scripts to validate and benchmark markdown structure policy checks (MD022, MD031, MD032, MD047):
scripts/test-markdown-policy.ps1scripts/benchmark-markdown-policy.ps1
Example:
pwsh -File scripts/test-markdown-policy.ps1
pwsh -File scripts/benchmark-markdown-policy.ps1 -Runs 5| Project | Description |
|---|---|
| 🌼 Pansy | Universal disassembly metadata format and toolkit |
| 🌺 Peony | Multi-system disassembler (ROM → .pasm source) |
| 🌸 Poppy | Multi-system assembler (.pasm → ROM) |
| 🌱 Game Garden | Games disassembly, editing, and recompilation |
Nexen is dual-licensed:
- Nexen Additions (Unlicense): All new features, modifications, and additions created for this fork are released into the public domain under The Unlicense.
- Base Code (GPL v3): The original Nexen code by Sour remains under the GNU General Public License v3.
See LICENSE for full details.
Nexen builds upon the excellent work of:
- Nexen by Sour — The original emulator codebase
- The emulation community for documentation and research
- Contributors and testers
Made with ❤️ for the retro gaming community