A couple readers have pointed out the recent disappearance of Silent Hill: Downpour from the Xbox Live store. I was able to confirm it’s no longer available where I am, and that Silent Hill: Homecoming and the Silent Hill HD Collection haven’t vanished with it, but the reason for its sudden removal is still a mystery.
My guess is this is just another example of a license expiring. That sometimes happens around this time of the year.
I’ve reached out to Konami for a comment, I’ll update this story if/when I hear back.

