Sega Japan announced today that the upcoming PS2 remake of the original Nights: Into Dreams will include a mode of play called Christmas Dream. To access this mode, which takes place in a snow-filled world and features Santa clothing for the Nights character, you'll have to clear the main game.
Fans of the original Nights will have probably made the connection by now, but Christmas Dream is based off Christmas Nights, a Christmas themed bonus disk for the original Nights that was given away to Sega Saturn owners both as a special pack-in with the system and bundled with a magazine. As with the rest of the remake, Sega has updated the visuals for the PS2.
The PS2 Nights: Into Dreams remake, Christmas Nights and all, hits Japan on 2/21. A release outside of Japan has yet to be announced.