The film's main downfall certainly has to be this kid, Jesse, who is far too perfect and intelligent to be credible (although he does make a pleasant change from the snotty, rude brats that often pop up in films these days). Also, he brings about plot holes such, as how can a boy of twelve be allowed to buy himself a plane ticket to traverse the continent, what kind of man takes his young son to a murder scene, why does the FBI give a kid access to their mainframe and why on earth is a grown man intimidated by this boy?
I think if you ignore the fact that there are many non-too-credible moments in the film, it does have the capacity to chill you. Certainly, the guy playing the killer is rather frightening. If not, you'll get a good laugh out of seeing the kid playing 'bad cop' as he tries to question a suspect, using fancy computers that are barely available now let alone in 1992/3 (his personal computer resembles something more suited to 'Star Trek') and solving the case while the grown FBI agents flounder around like incompetents.