Fez programmer Renaud Bedard notes "twenty thousand people" have played the game in the past 24 hours, more than have in its five years of development, adding: "So, as it happens, bugs popped up. Some pretty serious."

Bedard mentions that a "small subset" of older Xboxen with smaller hard drives can't run the game. He also notes the game has problems running off a USB stick and that in a "rare situation" - by exiting the game from the "wall village" interiors - a save file can corrupt. He admits it's "nasty stuff."

"We will be working internally and with Microsoft on those issues and let you know more later. It makes sense to issue a patch, but we don't currently have an ETA on it."

Those experiencing "game-breaking problems" should let Polytronic know by email.

"Sorry, and thanks for understanding!" He concludes, "And we're thrilled to see that the vast majority of you are enjoying the game as it was meant to be."