Call of Duty: Modern Warfare 2 (2009) for the Xbox 360, running natively on Linux and Windows.
Not an emulator: the game's executables are recompiled ahead of time.
No game files are included. You need your own disc.

• Campaign and multiplayer, with split screen for up to four controllers.
• Online with friends: private matches and system link, through Steam invites or on your local network.
• Sharper than the console: any window size or fullscreen; drawn at 720p, 1080p, 1440p or 4K, in 16:9, 16:10 or 4:3 (down to 640x480 for a CRT TV); antialiasing up to 8x; 16x texture filtering; sharper shadows; wider field of view.
• Your profiles: set your rank and prestige, unlock everything, open any mission.
• Custom maps (beta): maps made for the PC game, converted by the launcher.
• Xbox 360-style controllers, with rumble.

Not supported: ranked playlists, matchmaking without a server, and keeping a match going when its host crashes or loses the connection.

1. Download it for your system from the releases, and extract it anywhere.
2. Install: start mw2-launcher, choose INSTALL GAME and pick your ISO. The game is copied into game/ and updated to title update 6.
3. Play: PLAY CAMPAIGN or PLAY MULTIPLAYER. (mw2-sp and mw2-mp start the game directly.)

Everyone runs mw2-mp from the same release, with the same NETWORK chosen in the launcher.

Steam. With Steam running, the game shows as Spacewar. SYSTEM LINK lists the games every Steam player hosts, worldwide, and anyone can join yours. For a game among friends, host PLAY ONLINE → PRIVATE MATCH and choose Invite friends (or press F6): it lists your Steam friends who are playing. Your friend accepts in Steam's chat while their game is running. Other players see your Steam name. Without Steam running, it plays as LAN.

Server. Everyone on the same server sees each other's games in SYSTEM LINK, can join each other's private matches, and finds games together with FIND GAME, from anywhere. Whoever hosts a match plays in it. Enter the server's address and password under NETWORK; nobody but the server's owner needs to open a port. To run one, see docs/relay.md.

LAN. SYSTEM LINK finds games on the network by itself. In a private match, the lobby's Invite friends invites everyone on the network; start the others with MW2_LAN_ACCEPT=1. Two copies of mw2-mp on one PC can play a system link match, each with the controller that chose SYSTEM LINK in it.

Everyone must have the same release: the launcher updates it. Another release's games don't show in SYSTEM LINK, and joining one says Server is a different version.

The known security bugs in the game's 2009 network code are fixed (docs/security.md). It is still old code: play online only with people you trust.

• Steam: anyone on Steam can join a SYSTEM LINK game you host, and can reach your game while you host one. While you look for games in SYSTEM LINK, any game listed there can answer. Otherwise the game ignores traffic from anyone not in your lobby, and a private match is always among friends.
• Server: anyone on the server can join your games. The server sees all the traffic; the other players don't see your address.
• LAN: anyone on the same network can reach the game.

What the launcher sets is kept in a file named .env beside the executables, one setting per line. Environment variables work too.

Saves are in saves/ beside the executables.

Building, the source layout and how the runtime works: docs/building.md, docs/runtime.md, docs/switches.md and the rest of docs/.

GPL-3.0-only (SPDX-License-Identifier: GPL-3.0-only). It covers this project's own code: the runtime, tools, patches and build files. It grants nothing for the game: Activision's code and data, and the C++ generated from the game's executables, are not part of this repository and not under this license.

No game code or data is included; the builds only run with files from your own disc. Not affiliated with Activision, Infinity Ward, Microsoft or Valve.