This news corrects the previous assertion that the game would receive two-months of timed exclusivity on Xbox Live Arcade, which was first reported by Eurogamer after conferring with Konami representatives. However, US-based Konami reps could only confirm that the release dates of December 14 and 15 apply to the North American releases. European release dates weren't confirmed.
To add to the pre-release confusion, it was initially reported in an interview with GameFocus that the North American release date would be December 26. The new release dates of Dec 14 and 15 are nearly two weeks earlier than the release date that was initially revealed.