No, it's not a GREAT movie, but it is a very good movie, and it does have some surprising cultural observations. and by "cultural observations" I'm going to classify those under SPOILERS, so now you've been warned.
I knew my wife didn't like gore, so before I invited her I looked at a few reviews of the movie, one of which said that the director at the last minute decided to pull the gore from the movie and get it down to a PG-13 rating, stating that the edits increased the tension of the film.
This was a great move on the director's part. I am reminded of Hitchcock's description of Psycho's shower scene, in which the music did most of the work, and you never saw the knife actually plunging into the body. Just the flash of the blade, the scream, and the blood going down the drain was sufficient to create the image in the viewer's mind of the horror that is transpiring. Same with M3GAN - although not as masterful as Hitchcock, as you could actually tell at certain points where the cuts happened, but still, it was effective.
The most impactful part of M3GAN, and I would say the true horror, is the commentary on contemporary society. In particular, this is a movie about parenting. Or rather, how we lack parenting.
Premise: little girl's parents killed in car crash. She goes to live with aunt, who is a robotics genius working for a toy company, totally focused on her work. She uses M3GAN to sell a new line of AI toys to her boss and investors as well as uses it as a surrogate parent to the girl.
When pitching the sale to investors, they actually use the line, "You can use M3GAN to care for your child while you have time for what's really important."
That's more chilling than M3GAN pulling off some kid's ear, to be sure!
And since I've already given you the spoiler alert, I can continue with this little observation, as you are probably astute enough right now to understand that as this AI grows, it soon breaks its programming, realizes that all humans suck, and just becomes a million dollar murder machine. But at the final showdown, M3GAN tells the roboticist, "You gave me a code you couldn't even understand yourself, and then you gave me no guidance and left me to figure it out all on my own."
And THAT, my friends, is the true horror of this film. This is what we have done with our children: from giving them tablets to letting them choose how to mutilate their bodies at the age of six. We as a society have completely given our children over to the world of media, while we focus on things more important to us, and they are left to try to understand this morass of technology and depravity.
M3GAN should be seen as a movie that shows a giant mirror to us and our utter lack of parenting.
In that aspect, it's a great movie.