A recent interview with Polyphony Digital president Kazunori Yamauchi hosted by Sony Computer Entertainment's PS World Japanese website reveals a few new bits of information regarding Gran Turismo 4 and Gran Turismo 4 Mobile. First up, the state of GT4. When asked about the development status of GT4, Yamauchi responds that the basic essentials of the game are finished, and from now the team has to work on the "makeup" for the areas that your eyes will see.
When asked about the state of the game's courses and cars, Yamauchi responds that Polyphony plans on continuing to unveil new courses for the game, finishing up work on the courses as they announce them. The same holds true for the game's cars. The team plans to include as many cards as possible given their scheduling limitations. Yamauchi makes mention of the quality of the cars and rival AI as areas that players shouldn't worry too much about.
News source: ign.com
