Continuity breaks and plot holes you can sail a wooden boat through, pacing issues, and some really bad dialogue. Yes, I grew up with the books, as did my kids who watched with me. We were all prepared for alterations in story, but so much of it was unnecessary and caused us to spend way to much time with the "big name" actors chewing the scenery and the dialogue, whilst the "famous" five were very often absent. The kids were appalled, and I'm still bewildered at how this could be so bad. And don't get me started on the dialogue-drowning era-jarring electro-soundtrack and epilepsy-inducing titles!
Review of The Famous Five
