The popularity of achievements has driven game developers to find new ways to hook players in to committing time and money to their product. The player base of Xbox Live is one of the largest markets for achievement-focused players, and Xbox 360 games have been at the forefront of these attempts.
Prechievements whose conditions have been met are registered when exiting a demo play session and stored on the player's profile synced to Xbox Live. Once the player connects to the service while playing the full retail version of the game, those achievements are unlocked officially and Gamerscore points are awarded. The PSN system functions similarly with trophies.
Prechievements vs. XBLA Demo Achievements
The prechievement has only appeared in full retail games, not Live Arcade titles. A great majority of XBLA game demos display a variant of the prechievement, whereby once the criteria for an achievement was met, a notification would be displayed prompting the user to purchase the full version of the game immediately in order to unlock the achievement and the Gamerscore. This prompt tries to encourage the impulse purchase of a title with the suggestion that failing to purchase results in the loss of an achievement.
Where these differ from an actual prechievement, is that if not immediately purchased, any achievement goal met is lost upon quitting the game, and would have to be re-satisfied once the full game was purchased at a later time. Prechievements are earned and stored in perpetuity – in a sort of achievement buffer – ready to unlock immediately once the full game is first played.
Unlockable Avatar Awards and Gamer Pics are also being used more often as the hypothetical "dangling carrot". The same method as XBLA Demo Achievements, applies to these rewards.
For more information on the development and awarding of 360 achievements, see the official Xbox Engineering Blog.
Gamerscore-Enabled Game Trials
PlayStation Plus Full Game Trials
One of the subscriber features identified in the PlayStation Plus FAQ, is that full 60 minute demos of downloadable retail titles allow any trophies earned to be unlocked upon purchasing the full version.
Trophy-Enabled Game Trials
When the demo for Yakuza 6: The Song of Life was uploaded in western territories, the full game was mistakenly uploaded instead, allowing players to unlock trophies while the "demo" was available. However, it was soon taken down and licenses were revoked, meaning people who had downloaded the demo previously could not redownload later.