The Xbox Live Games Store, formerly the Xbox Live Marketplace, allows Xbox 360 and Xbox One users to download different kinds of games. Downloads were originally purchased using Microsoft points, but were changed to real currency prior to the launch of Xbox One.
The Marketplace also allows players to download add-ons to their games; maps, extra episodes or levels, music tracks etc. The majority of the downloads are stored on the 360’s hard drive.
On November 19, 2008, Microsoft released the New Xbox Experience, which completely overhauled the Xbox 360 Dashboard, and added several new features.
Originally, during the Xbox 360 era, the Xbox Live Marketplace was split into three sections: Xbox Live Arcade, Xbox Live Indie Games and Games on Demand (retail games). There is also a Game Room application that lets you download and play old games through the application that must be downloaded through the marketplace.
Xbox Live Arcade
Xbox Live Arcade is where game publishers release download-only games. It started with mostly rereleases of classic arcade titles like Gauntlet, Smash TV, and Frogger, but later expanded to expanded to new, original titles like Shadow Complex, Castle Crashers, and Brothers: A Tale of Two Sons.
Games on Demand
Games on Demand allows users to purchase retail Xbox 360 games as well as original Xbox games that have been made backwards compatible. Certain games have been released simultaneously at retail and on Games on Demand (i.e.Crackdown 2), however there is usually a delay between the retail release and the digital release.
Xbox Live Indie Games
Xbox Live Indie Games are games made by independent developers and are self-published onto the marketplace. The price of these games are generally cheaper, but they are not rated by the ESRB nor does Microsoft ensure the quality of the game.
De-listed Xbox 360 Games
Some games have been de-listed from the marketplace, here's a list of them all. These games are still available to download from your purchase history if you purchased them before, however they can no longer be purchased.