Quote from Michael Lynn on September 29, 2023, 23:49

This is actually a 2 disk demo but the zip file on this site only contains the first disk.

Both disks can be downloaded from here:
https://demozoo.org/sceners/31556

The download link is also incorrect there and the file is actually stored here:
https://ftp.untergrund.net/users/ltk_tscc/fujiology/ST/C/CUBBIT_M/STOSSER.ZIP

The author's name is Martin Cubitt so the directory name should be CUBITT_M.
I'm not sure if the DemoZoo editor will correct this in the future.