Alyx Multiplayer

Play Half-Life: Alyx with your friends. One of you hosts, the others join, and you play through the story together. Works with a VR headset, or with mouse and keyboard thanks to HLA NoVR.

Download the latest version (Windows, free)

Install

1. Run AlyxMP-Setup.exe. If Windows warns you, click More info → Run anyway.
2. Want to play without VR? Leave Install HLA NoVR ticked.
3. Click Install, then Play. Next time, open Alyx Multiplayer from the Start menu.

Everyone needs the same version of Alyx MP. SteamVR has to be installed, even without a headset.

Play together

• Host: type your name, click Start hosting and send your friends the address it shows.
• Join: type your name, paste the host's address and click Join.

The game starts on its own and puts you right next to the host. If your friends can't connect, the host needs to open TCP port 27420 on their router, or you can all use a VPN like Tailscale.

In the game

• Y to chat, ESC for settings.
• A dot in your crosshair means you can use what you're looking at.
• Carrying something? Hold the right mouse button and move the mouse to turn it. E drops it.
• You see each other as Alyx, with your names above your heads.
• Doors, puzzles, items, enemies and story moments are shared, so you're always in the same world.
• To move on to the next level, everyone has to stand in the loading zone at the exit.
• If you die, you come back next to the host. If something looks out of sync, click Resync my world.
• The game saves every 5 minutes and after every level change.

Good to know

• Enemies are run by the host's game: everyone sees them in the same place, going after the same player, with the same health, and they die for everyone at once.
• Alyx MP adds a few small things to NoVR: a new HUD, auto reload and one line in its interaction script. Uninstalling removes them.
• The launcher tells you when there's a new version: click Update at the top, or tick Update automatically under update log.
• To uninstall, run AlyxMP-Setup.exe again and click Uninstall. Your saves stay where they are.

Build it yourself

Install the .NET SDK, run build.ps1, and the installer lands in dist/.

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Fan-made and not affiliated with Valve. HLA NoVR is made by the NoVR team (GPL-3.0).