Stupidity: The climax takes place during the launch of the "Buddi 2," a hotly anticipated tech gadget. The entire film has been leading up this point, and it's a big deal that it's being launched. And yet, there are no more than maybe 20 people waiting. Not a mistake per se, but totally unrealistic compared to the huge crowds these sort-of launches typically bring in.
Suggested correction: Bear in mind, this is just a cheap retail store in downtown Chicago; presumably, every major department and toy store across the country is having a similar event, so this opening would logically only draw people in the neighborhood with children the right age and willing to pay the opening-day price. Plus, we hear a voice on a radio warning of upcoming rain. The report is proven wrong since there's no rain for the rest of the scene, but even a warning of rain would ward some off.
I'll agree to disagree. I live in a relatively small, quiet town in upstate, New York, and events like new tech-launches (new iPhones, video games, etc.), movie premieres, anticipated book releases, etc. still regularly bring in pretty huge crowds at virtually every participating store. (Ex. Lines going out the doors and wrapping around the building.) Heck, I know someone who tried to get the last "Harry Potter" book opening night and couldn't because every local book store was packed completely full. So I have a hard time believing the crowd would be so small. The fact this movie also takes place in a pretty major city like Chicago is another strike against it.
Stupidity: When Chucky was hanging Karen using the forklift, why didn't she just lean back and sit on the forks to stop the anchor of the rope from going higher than her? Not anything a forklift-operator would recommend, but it beats being hanged.