You may have heard that the production of the "Black Christmas" remake was troubled because of disputes and quarrels between the studios and the director. Dimension Films wanted it to be a gory and brutal torture-porn-fest, while Glen Morgan (director / writer) wanted it to be more of an homage to the original, which resulted into countless re-writes and various re-shoots. Also, at the request of Dimension Films, additional footage was shot solely for advertisement purposes, much to the disgust of Clark who had no idea about this footage.
What's even more weird: 3 different versions of "Black Christmas" were released on DVD in 3 different countries (USA, UK & Germany), all containing different scenes, different cuts, different endings etc.
Without futher ado, here's a little overview about all the alternate and deleted scenes (DVD Bonus), as well as the scenes that were shot for the trailer:
Alternate / Different Scenes
~ Opening (Clair's Death) - US only
The opening scene is slightly longer incl. a zoom on Agnes hiding under a Christmas tree, and a close-up of Agnes' hand + pen.
~ Billy kills the Cell Guard
Germany & UK:
While the cell guard's on the ground searching for Billy, the camera tracks towards the empty bed. Suddenly, Billy appears behind the guard and stabs him with a candy cane.
While the cell guard's on the ground searching for Billy, the camera tracks towards the bed and we get to see Billy crawling out, standing up and killing the guard with the candy cane.
After the candy cane has fallen to the ground, there is one more shot of Billy leaving and the cell guard bleeding from his neck.
~ Melissa's Death
US & Germany:
Agnes puts a garbage bag over Melissa's head, but she breaks free and flees into a room. After a little fight, Agnes grabs an ice skate and throws it at Melissa's head. Result: a fatal head wound.
Agnes sneaks up to Melissa, puts a garbage over head, drags her down to the ground, pulls out one of her eyes and eats it. Then, Agnes sticks a finger into Mel's eye hole (Mel's still alive) and drags her away.
~ Lauren's Death - US only
Billy and Agnes sneak into Lauren's bedroom. Billy crawls under her blanket and starts to fondle her. Lauren wakes up, panics, grabs the statue of a unicorn and tries to stab Billy with it, but she misses him. Suddenly, Agnes attacks and chokes her, grabs the unicorn and stabs her in the face.
US & Germany:
Reporter talks about the incidents. A pathologist gets killed by Billy who crawls out of a body bag. Kelli and Leigh talking. Nurse takes Kelli away. Leigh leaves the room to investigates on some strange noises. Leigh returns and gets killed by Agnes. Kelli returns, gets attacked by Agnes. Eventually, Kelli electrocutes her with a defibrilator. Billy appears and hunts Kelli through the corridors, but she manages to throw him over a balustrade and Billy ends up skewered on a Christmas tree.
UK (Scene also known as Alternate Ending #2):
Kelli and Leigh talking. Detective takes Leigh away because she needs to identify a dead body. Meanwhile, doctors try to reanimate Billy but fail. Leigh returns and gets killed by Agnes. Kelli returns, gets attacked by Agnes. Eventually, Kelli electrocutes with a defibrilator. Kelli's parents pick her up from hospital. The final shot is a "Peace on Earth" sign on a door.
Deleted / Unused Scenes
~ "Someone in the Attic"
Camera pans over the house. We get to see a few of the girls in their rooms telephoning, smoking etc. Then, we're suddenly in the attic. A rocking chair, something's moving in the dark. POV shots of a person walking towards the attic ladder.
~ "Christmas Ringtones", "Gift Exchange", "The Girls discuss Kyle & Eve" & "Phone Call from Dana - Extended Version"
4 rather unimportant scenes: girls talk about ringtones, one of them receives a huge dildo as xmas present, and some more talk about Kyle and Eve, ending with Lauren puking all over the table + a longer version of the scene where the girls receive a call from Dana.
~ Lauren's Death - Alternate Version
Agnes enters Lauren's room, puts a snow globe on the table, walks towards sleeping Lauren and stabs her with the glass Unicorn.
~ Alternate Ending #1
Kelli and Leigh talking. Suddenly, Kelli's phone rings. It's Kyle... or, let's say, it's someone calling from Kyle's telephone. Since Kyle is already dead, it's obviously either Billy or Agnes. The girls are frozen in shock, the camera fades outside.
~ Alternate Ending #3
Billy is dead. Kelly is relieved and leaves the hospital. Then, we get to know that the body 'disappeared' and the hospital staff rushes to search for it. Camera pans into a room and we see someone looking through a venting slot. Is it Billy? Is it Agnes? Who knows...
Scenes that were shot for the US theatrical trailer
A girl (not in the actual movie) on a frozen lake, wiping snow off the ice. We get so see a body, frozen with its eyes open, which suddenly reaches its hand through the ice.
Dana falls off the roof, tangled in Christmas lights, and gets dragged under the house by some kinda mechanical Christmas-lights-machine.
Melissa in the hallway with a flashlight while Billy "levitates" on the ceiling, ready to strike with an axe.
Next to a few unused shots and images, and some lines that didn't made it into the movie (Killer on the phone: "All is calm, all is bright. Who is in my house tonight?", there was another promo scene in one of the TV spots.
According to Imdb, there's a doorbell ringing, one of the girl (armed with a shotgun) opens the door, saying: "Merry Christmas, Motherfucker!"