I saw a movie hen I was a baby, back in the early 80s, so it must come from the 70s or early 80s, about two siblings, boy and girl, who get chased/transported to an alternate dimension-type of world where an evil mad scientist type of villain is chasing them. The villain reminds of Eugene Levy, but I’m sure it’s not him. The world they’re trapped in and trying to escape from is almost animated, but that could be because of the technology for the time. Lots of cheesy special effects.