What I found brilliant about this movie was that the makers realized that the simplest, cheapest, yet most massively effective way of visualizing travel between alternate dimensions was via mere jump-cuts in the editing.
There were only a couple of CGI bits, the rest was all discontinuity: Somebody gets tossed out of frame-right in one locale, then lands from frame-left in a different one.
No fancy transition, just blink and you're someplace else. Kinda like what happens in one of Larry Niven's "Known Space" stories when a stasis field activates.
I had the movie on VHS about 10 years ago, but I was never able to find it on DVD.
[yt]http://www.youtube.com/watch?v=1IENs1gylgk[/yt]