You are not wrong, it's a laserdisc console so it was on laserdisc. Also it was released on the arcades(again on laserdisc, of course) with a keypad and some kind of save feature, very ahead of it's time on that.
However the versions are not the same AFAIK. Since the Halcyon version used a two-sided laserdisc and the arcade used a single side scenes had to be cut. I don't know if the DVD version includes everything. However note that it only has half of the storyline since the planned sequel never materialized. I read somewhere that another (later) game was kind of a sequel and includes the rest of the storyline, you should he able to find the title easily if you are interested.
The Halcyon simply was too expensive. Just the laserdisc player was horribly expensive but it also had a speech module, voice recognition and artificil intelligence! It was simply too experimental, while the technology existed it was not developed enough for what they wanted to do.
Take this page as a starting point
http://www.dragons-lair-project.com/co ... s/halcyon/
Hope I helped!
