The promotion on Dreamcast is an unknown universe. It is difficult to document this penultimate step in the conception of Sega's last console and its games. Each marketing territory for the Dreamcast used different techniques and processes. The publishers also had different marketing strategies.
Unlike in Europe and the United States, Sega Japan used pressed GD-Roms containing videos. They were used in demonstration kiosks hidden in the four corners of the country of the rising sun.
The most interesting and emblematic demo disk is probably the "Dreamcast Promotion Disk":
The "Dreamcast Promotion Disk" is a promotional disk for the Sega Dreamcast. Although the disc is machined on a GD-Rom, it contains only video clips, no interaction (like playing) is possible.
You can download it below: Dreamcast Promotion Disk (Oct 22, 1998 GD-Rom Dreamcast)