Wikipedia
Detalion was a Polish video game developer. It was closed down due to financial difficulties in March 2005. They developed such notable adventure games as Reah: Face the Unknown, Schizm: Mysterious Journey (published as Mysterious Journey: Schizm in North America), Mysterious Journey II, and most recently, Sentinel: Descendants in Time (later re-released as Realms of Illusion). These games (particularly Mysterious Journey: Schizm) were noted for the complexity and great difficulty of their puzzles, and also were hailed as having some of the best graphics in the industry at the time.
After Detalion's disestablishment, its founders went on to create Detalion Games and Detalion Arts to take its place. Now both are defunct as well.
Detalion was one of the first developers to use the DVD-ROM disc as an effective medium for software distribution.