How do you play "Left 4 Dead" online?

From the main menu of "Left 4 Dead," choose Campaign, Versus, or Survival. Choose a running server from the Source server menu, or create your own listen server by clicking Create Server. Then, depending on whether the server is public or private, invite friends, or wait for random players to join the game.

"Left 4 Dead" like most Source Engine games with online capabilities, accesses multiplayer options on the main menu. In the case of "Left 4 Dead," all modes save "Single Player" have multiplayer capabilities. Ensure your computer or console connects to the Internet before opening the game, and check any firewall or anti-virus software installed for blocking or exception query messages. Depending on the game mode and server, the game fills any empty spots with AI players until a human player joins.

Multiplayer games include ping estimates in the server and scoring menus. Ping is a measurement of how in-sync the players' connections are. A higher ping number means more delay, while a lower ping number means less delay between the actions of a player at his keyboard and the execution of those actions in the game server. A particularly high ping results in frame rate drops and lag or game slowdown on the offending player's computer.