Game Description:The first glimpse of the series on PlayStation 3, Gran Turismo HD Concept is a series of downloadable samplers of Gran Turismo based on GT4 but running on an early version of the GT5 engine. As described by producer Kazunori Yamauchi, the first Concept is a first-look at the high definition graphics provided by the PlayStation 3. The second Concept download includes Polyphony's next generation driving engine.
Upon downloading Gran Turismo HD Concept, PS3 users have access to the Eiger Nordwand course and can compete in Time Trial races to collect and unlock new cars. Upon unlocking the initial 10 cars, the player has access to 10 more "Tuned Cars," as well as access to a new driving mode called "Drift Trial", where the player's drifting technique is tested, rather than their lap time.
The game was originally to include two special modes: classic mode was to be a micro-transaction version of GT4 running in high definition and with online play, and gamers would be able to play online with the cars they have downloaded (and paid for) through the PlayStation Store. Premium mode was to be a single player preview of Gran Turismo 5, featuring a full-fledged PS3 graphics engine and detailed tracks and car models. The concept was scrapped late in development so that creator Polyphony Digital could focus on Gran Turismo 5, with GT HD Concept being a series of sneak-peek demos instead of a full micro-transaction online game.