Oddly enough the printed form wasn't the only one The Od Island was presented in. Back in a day we had those things called Filmoscops. Basycally it's a slide projector, but insted of separate slides it utilized continuous strip of film (diafilm) that you wouldscroll down from one frame to another. In soviet times the made a shitload of diafilms covering all sorts of topics, but mostly educational and... childrem entertaining, I guess. You would have films with folk tails popular cartoons adaptations... and that one with The Od Island. At least we did. I don't know where's that film now, maybe I'll find it someday... and I'll be happy (probably). But you don't have to wait untill then because I found this video:
It shows the whole film from begining to end. The commentary is in Russian but trust me, you won't miss anything but cringeworthy jokes about square butts. Also, I suppose, I have to mention the video contains some moderate nudity.
I wonder, wether they decided to go with the landscape page orientation in the book because they knew beforehead the'd gonna put it onto diafilm as well. I guess, we'll never know.