Game Sessions is a beta service which offers the chance to sample games on Steam. This features the ability to purchase full versions from within these sample sessions, and the system also supports game rentals. Ryse Son of Rome is the newest game they feature, saying Crytek is allowing players one trial of Crytek's action game that can run as long as 24 minutes. "We passionately believe that people will buy more games if they can try them first," explains Ed French, CEO of GameSessions. "With our free trial service our mission is to deliver more great game experiences to more players." They also claim compression-related download speed advantages:

GameSessions’ proprietary technology ensures publishers’ content is secure, so ensuring the best content can be available, and typically downloads games 3x* faster. The service also helps to avoid downloading games that won’t run well on users’ hardware, and final peace-of-mind comes from the guarantee of always playing a game before purchase.

Users can now download and play the free trial of the stunning ‘Ryse – Son of Rome’ on PC as part of the Beta 2 phase. More exciting titles will be added in the run up to the full launch of the service in early 2015.
…
* Benchmark tests show games reduced by 50% to 80% using GameSessions compression technology.