Japan delay not related to game itself
Reported yesterday on sister site GameGrep, it seemed as though the Japanese version of Sonic Unleashed would be getting some special treatment, with some extra development time to be taken to "improve the quality of the game" (this coming from the translation of a post on the official game page). According to Sega, this was a misunderstanding, and the quality of the game will be unaffected. I can only assume this was a translation mistake -- never try to translate news if you're not totally confident!
Here's the response from the company:
"To Sonic fans living outside of Japan: In our previous November 7 post to this home page, we informed you that the release date of Sonic Unleashed in Japan on PS3 and 360 will be delayed.
Based on that announcement, some fans living overseas have become concerned that there will be a difference in quality between the version of the game released in Japan and the version released outside of Japan. This is not the case and we apologize for this misunderstanding.
The difference in the international release dates is based on the sales strategy and the manufacturing schedule. There will be no quality difference between the North American/European/Asia release and the Japanese version."
Good news!
The game will be released in 2009 in Japan, and is headed for console releases in North America and Europe this month (what day depends what console you're buying it for).
Guess that's just changing in-game billboards or somethin'...