It is unfortunate that this film hasn't, as far as I can tell, had a DVD release, because although it does have its flaws, it is certainly a far better film than a lot of the direct-to-DVD schlock that have been vomited out over the last decade. I suppose Mann might be embarrassed by it's rather poor performance at the box office and general panning by critics at the time, but honestly I don't think it's that bad for an 80's supernatural horror film. Despite this being one of his earliest theatrical works, Mann's eye for direction and strong stylistic sensibilities give the film some very striking visuals, and the score - performed by Tangerine Dream - adds to the feeling of surreal supernatural horror.
Right now, I think the only place you'll be able to find this film is on Netflix, but fortunately the transfer looks very good - it's clear they didn't just dupe this off of an old VHS tape. Performances by Scott Glen, Gabriel Byrne, Jurgen Prochnow, Ian Mckellen, and William Morgan Sheppard, among many others, are quite strong. If you have Netflix Instant available to you, I really suggest you give this film a try.
Here's a poorly captured trailer for the film: