Fallout: New Vegas (nv-rs)

Fallout: New Vegas, rebuilt in Rust, aiming to play exactly like the original.

nv-rs is a new engine for Fallout: New Vegas, written in Rust. It runs the game from your own copy's files. The goal: the game looks and plays exactly like the original, while everything underneath becomes a modern 64-bit engine: no 4 GB memory limit, every CPU core in use, high frame rates, fast loading, far fewer crashes, built-in modding and more platforms.

[!IMPORTANT] nv-rs is an independent project, not affiliated with or endorsed by Bethesda Softworks, ZeniMax Media, Obsidian Entertainment or Microsoft. It contains no game files; you need your own legally obtained copy of the game. See LEGAL.md.

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Play the preview

Download the Windows preview: you need Fallout: New Vegas (version 1.4.0.525; only the Steam version has been tested so far) installed on a Windows PC.

1. Extract the ZIP to a folder of its own, for example C:\Games\nv-rs.
2. Double-click Play.exe. It finds your game and starts it.
3. Import my saves.cmd brings your saves over; Settings.cmd has the display options and the game fixes.

It never changes your game, your saves or your settings: everything it writes stays in its own folder. Windows may warn because the program isn't signed. It's a preview: so far it has only been run on one PC, so please report how it runs on yours (press F12 in the game to make a report). Keyboard and mouse only for now, and mods that need script-extender plugins (xNVSE, JIP) don't work yet. The download page lists what works and the known issues.

Where it stands

Playable. The whole game runs on its own translated code: the opening, the open world, quests, dialogue, combat, V.A.T.S., the Pip-Boy, saves, mods and the DLCs, with the original graphics and sound. Bugs remain, and it's slower than the original in busy places for now.

Next: moving the game's systems to native 64-bit Rust, one family at a time. That's what lifts the 4 GB memory limit, puts every CPU core to work and brings the speed. After it: new graphics on wgpu, a built-in script extender, more platforms, co-op and VR.

Progress

The bar counts how much of the original game's code is translated. That part is done; the table shows what's left.

	System	Status
✅	The whole game: movement, physics, animation, graphics, sound, combat, AI, quests, dialogue, menus, saves, the open world and the DLCs	Translated, checked against the original and playable
✅	Fixes: bug fixes on by default, the original's behaviour one setting away	First fixes in
✅	Windows preview	Released
🔨	Native 64-bit code: speed, no memory limit, every core in use	Started
🔨	Built-in script extender: xNVSE's and JIP LN's script commands, with nothing to install	Started
⬜	Modern graphics (wgpu), more platforms, co-op, VR	Planned

✅ means working, not free of bugs. The details are in docs/SYSTEMS.md and docs/MILESTONES.md.

Why it's different

• Translated from the original, not guessed. The original game's program is translated into Rust piece by piece, and every piece is checked against the original.
• Your game, your files. nv-rs reads the game's own data from your installation and never changes it.
• Modern underneath. The original's look and play are the reference; the internals are being rebuilt in 64-bit Rust, whose memory and thread safety rule out whole classes of crashes.
• Better where it doesn't change the game. Fixes and upgrades are switchable; the original stays available.
• Mods keep working. Regular .esp and .esm mods load the way they do in the original.

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How it's made

To be upfront: nv-rs is built almost entirely with AI coding agents (mainly Claude). The maintainer directs the project: the plan, the priorities, playtesting and what gets merged.

What keeps it honest is the method: agents don't get to invent behaviour. Every piece of logic is translated from the original game's program, marked with where it came from, and checked by tests, by running it against the original's own code and by recordings of the original game. Everything is in the open, so judge it by how it plays.

Get involved

• Play and report: try the preview and open an issue for anything that differs from the original.
• Contribute: read CONTRIBUTING.md (and give AGENTS.md to your agent), say in an issue what you'd like to work on, then open a small pull request.
• Chat on the project's Discord.
• Support the project on Ko-fi. It goes to the AI time the work runs on, which is what limits how fast the project moves. It's a voluntary gift: it buys nothing and promises no release date, and you still need your own copy of the game.
• Build from source: see docs/PLAYTESTING.md. For how it works, start with docs/ENGINE_PORT_PLAN.md; every document is linked from docs/README.md.

Final decisions rest with the maintainer, slaterain (docs/GOVERNANCE.md).

Legal and license

Original code is licensed under the GNU GPL v3 or later. The licence covers only original work. Fallout and Fallout: New Vegas are trademarks of their respective owners. Read LEGAL.md for the full notice.