This was pretty good. A doorway opens in the woods. (I always suspected this would happen!) Something comes out, into this world. An evil something. Dean Koontz has especially blossomed in his writing since this book was published. You especially notice if you read the Odd Thomas series, and then read this one. It's good, but not the vivid, expressive page-turners you'll find in more recent Koontz work.
I loved how the kid saves the day in this one, and I love how he does it. Even creepier: You know at the end, the alien spawn isn't really dead. Not really. The immediate danger is over, perhaps, but you have the feeling it'll be back one day. Good stuff!