An old film professor of mine used to talk about something called the 'uh-oh moment'. It was that moment, usually at the end of a foreign and/or artsy-fartsy film, when the credits started to roll and you realized that the movie was over and you really had no idea what it was thematically about. That in itself is not necessarily a criticism of the movie. Some films like John Huston's The Dead require either a second viewing or a familiarity with the original source material to really get it, since the movie only really reveals itself at the climax. But it is absolutely a problem for a movie when you realize that not only did you have an 'uh-oh moment', but that the filmmakers probably had one of their own upon viewing the final cut.
Trick 'R Treat is a stunningly lifeless and seemingly aimless would-be horror comedy. It is a muted and rushed affair, seemingly edited without discipline and constructed without purpose. It relies solely on the talents of Brian Cox and Dylan Baker to give the material more worth than it deserves. The picture is basically a horror-anthology, mixing four brief tales of terror that take place over a single Halloween night. Alas, it is not scary and it is not funny. And its anthology structure is undone by the needlessly non-linear narrative that spends much of the middle act bouncing between the two least interesting of the four stories (an urban legend involving a doomed school bus and a would-be twist on "Little Red Riding Hood"). At 82 minutes, it has little time to give weight and character to any of its tales, yet it there is so little to chew on that the film drags despite the slim running time. The film also runs afoul of narrative logic in its strained attempts at interlocking each of the four stories, which theoretically happen within about the same two-hour period.
I have no idea where the geek-love for this film comes from. There are plenty of worthwhile horror films that tragically end up going straight-to-DVD, but this is not one of them. The film is above all else dreadfully dull because it lacks anything even approaching substance and fails to deliver even the cheapest of thrills. This was not a case of Warner Bros cruelly regulating the film to a home-video debut out of some evil motives. Trick 'R Treat is just not good enough to justify a theatrical release. Even with a few moments of cleverness from Dylan Baker as the world's least competent serial killer or Brian Cox stuck in his own Trilogy of Terror rip-off (you can guess which story), the picture has no weight and is of no consequence. It even falls well short of the standard set by such cult horror films as Midnight Movie or Murder Party. Do not believe the hype. Trick 'R Treat is all trick and no treat.
PS - for a truly terrifying horror film, rent or buy The Children instead. It's truly one of the best direct-to-DVD horror films ever made, if not THE best.