Executive Meddling: The original version of the remake had, among other things, more character development and deaths more akin to the original; Dimension Films stepped in and started demanding rewrites and re-shoots (they're infamous for this sort of thing, see Halloween: The Curse of Michael Myers and Hellraiser: Bloodline) to the point that Director Glen Morgan has gone on record to say he HATED the move
Meaningful Release Date: The remake opened in the US on December 25, 2006. The UK got it ten days earlier, on December 15th.
Originally the big twist was that Billy had died at the asylum and it was Agnes doing all the murders. Agnes was only his half-sister not his sister/daughter, Leigh was suppose to live at the end, and the movie was suppose to end in a similar manner to the original with Leigh and Kelli getting a phone call from Kyle's Cell
Glen Morgan wanted Andrea Martin OR Margot Kidder who played Ensemble Dark Horse Barb from the original to play the house mother. The house mother in the remake's first name is Barbara, an obvious homage to Kidder's character, despite Martin playing the role.