Like the PSP port of Myst and RealMyst, the DS version includes the lost Rime Age level. This age was designed for the original Mac versions, but due to space limitation it got cut from the final shipped game. If you play the though the adventure successfully you'll discover a new book that, once deciphered, will transport you to the arctic Rime Age.
Myst DS - What's New - The Rime Age
Image © Empire Interactive Ltd, Myst © Cyan Worlds, Inc.
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