Steam content delivery system
Integral to Half-Life 2 is the Steam content delivery system developed by Valve Software. This allows customers to purchase games (or any other software) directly from the developer and have it downloaded directly to their computer. This system also allows "micro updates" to games - games are continually updated and only the most recent version is allowed to be run. This makes it much harder to hack the game to introduce cheats or to play online with a free 'pirated' copy. All users playing a single game must also have an account on the Steam servers to play the game. Steam is also used for finding and playing multiplayer games.
Some users have had numerous problems with Steam, enough so that the delivery and multiplayer client is a well-marked part of the game, in some cases enough to prevent a reviewer to recommend the game, and in almost every case enough to lower the review score. Long download times, updates and internet checks that are sometimes unnecessary characterize some negative views of the Steam client.
A 1 GB portion of Half-Life 2 became available for pre-load through Steam on August 26, 2004. This means that customers could begin to download encrypted game files to their computer before the game is released. When the game was released in the shops, customers were able to pay for the game through Steam, unlock the files on their hard drives and play the game immediately, without having to wait for the whole game to download. The pre-load period lasted for several weeks, along with several subsequent portions of the game being made available, to ensure all customers had a chance to download the content before the game is released.