It's true that I struggle with this thought process when I'm reviewing a child-oriented horror film. I feel like the film has to have this perfect balance that is near-impossible to achieve. It has to retain the attention of the kid, produce light-hearted material to keep the tension light, and introduce the horror genre in mild, yet effective ways that somehow cause a temporary reaction without haunting the child's thoughts on the way to bed. I feel like Goosebumps achieved this balance rather well.
The lead antagonist found in Slappy the ventriloquist doll was a solid choice leaning towards traumatizing. His Joker-like approach to campy one-liners helped ease the tension of the character, but his overall presence felt a bit too creepy for the youngest of viewers. In particular, the character's final line almost felt like a punch to the gut of any parent hoping to lay their kid to bed that evening without a mid-night scream of Slappy waiting in the closet. While he seemed the obvious choice for the lead antagonist role amidst the options RL Stine offers, the maniacal doll nightmare staple in nearly every childhood doesn't need any fuel to keep the fire burning.
Jack Black is his usual ridiculous self. Considering I think he never takes himself seriously in front of a camera, his complete lack of acting efficiency on screen is dismissed for his odd, yet sometimes charming humor. The acting from the younger stars flirts with deplorable, as they struggle to deliver lines that seem copied-and-pasted from similar 90's films. But, for the audience, they do just fine.
The scares seem cleverly balanced with humor, like mildly delivered Ghostbusters moments, but with less wit and more cartoonish behavior. At times it felt like the failings of the Scooby Doo live action film were seeping in, but this film managed to retain more dignity than that farce.
I was most disappointed in the selection of featured monsters. I enjoyed RL Stine as a child because of his interesting and unique creature concepts. To go with the werewolf, yeti, doll, and giant insect tropes as the primary assailants made the creativity fall flat, particularly in the context of the options at hand.
The horror for a kids movie was probably spot-on, but it's hard to determine its impact as an adult. You hope it falls into that fear sweet-spot, somewhere in between needing the nightlight turned on and unable to sleep for weeks. I think they managed to pull this off effectively, and hopefully, successfully, turned the film into a proverbial Camel Cigarettes ad for future horror movie fans. Get them hooked early without scaring them away. Easier said than done.