As television shows and movies get a second life on DVD, so do video games that can be downloaded after their original boxed release in stores. Indeed, the trend toward making more video games available via download goes beyond casual and retro arcade titles. This mode of distribution is breathing new life into whole back catalogues of older games, while generating fresh profits for publishers.

Xbox Live has devoted an entire channel of its on-line marketplace to what it calls Xbox Originals, games created for the original Xbox that are still worth playing on the Xbox 360. Halo: Combat Evolved, for example, can be downloaded for 1,200 Microsoft Points (about $17).

Browsing the list of older titles, it’s clear that 2005 was a great year for the Xbox. Jade Empire, Psychonauts, Ninja Gaiden Black, and Tom Clancy’s Splinter Cell: Chaos Theory were all released that year. All are available to download and play on your Xbox 360. Check your hard drive’s capacity, though, as most of these games require about four gigabytes of space.

Encouraging gamers to download older titles makes sense for game companies because the cash that comes in is pure gravy. There are no packaging, distribution, or retail costs involved in making publishers’ backlists available on-line.

Just as the period between a film’s theatrical premiere and its DVD release has been getting shorter, so too is the lag time between the issuing of a game’s boxed and downloadable versions.

Last January, Electronic Arts’ Burnout Paradise was released in stores at the price of $59.99 for PlayStation 3 and Xbox 360. In September, it became available on the PS3’s PlayStation Store for $29.99. Also available from the PlayStation Store, for only $14.99, is Ratchet & Clank Future: Quest for Booty. It’s a short adventure that picks up a year after the retail-released Tools of Destruction left off, and it amounts to an episodic extension of that game.

Some recent titles from Sony Computer Entertainment—Gran Turismo 5 Prologue, SOCOM U.S. Navy SEALs: Confrontation, Warhawk—were released in boxed and downloadable versions at the same time. Eidos did the same thing with Tomb Raider: Anniversary, a remake of 1996’s original Tomb Raider game.

Simultaneous releases are a step toward the end of traditional retail distribution. Developers and publishers like that they get to keep more of the sticker price with downloads. Cutting out retail distribution not only removes packaging and shipping costs. It also means that the amount of money typically kept by the retailer—between 40 and 60 percent of the shelf price—goes into the publisher’s pocket.

But it won’t do for publishers to offend retailers too much, which is why the digital versions of most new titles cost the same as the boxed version. While digital distribution is growing, it’s still small compared with the sales generated by the retail giants.

When a significant percentage of gamers are purchasing their games digitally, you can expect prices of downloads to drop.

In the meantime, Sony is cleverly differentiating its retail products from its downloadable versions by adding value to them. The boxed versions of Warhawk and SOCOM, for example, shipped with a Bluetooth headset that can be used to chat with other players on the PlayStation Network. And the only way you can get SOCOM’s making-of Blu-ray disc is by purchasing the game at a bricks-and-mortar store.