I had the VHS copy of this and the little kitten softly "meow"ing for help as he was about to be eaten by the rats was very disturbing. Especially when he was trapped in his own home and his mom and aunt couldn't find them.
EDIT: Here it is in full! God what a throwback. As messed up as this story is, I loved it as a kid and would watch it all the time.
Honestly, it's not nearly as disturbing as those. Watership Down sticks with you for life.