WolfSpirit
Not a dictionary. Or a search engine
I didn't mind that film, although I watched it as an adult and not as a kid. If I had watched that in childhood, I might have thought differently.
To be honest, and since we're talking about Don Bluth works, I found An American Tail to be more disturbing (and depressing).
Saw NIMH, Or bits of it, three times, at three different ages. First two scared the hell out of me, third, I couldn't figure out what had been so scary. Go figure. Then again, I always was the kid who was easily scared by things everyone else had gotten over being scared of. And didn't react to other things that did upset other kids. (Then again, they likely didn't have families who constantly drilled it into them how "defective" they were, and that they never should've existed to begin with.)