Note: This review contains spoilers for the original “Saw.” If you intend to see it but haven’t yet, save this column to read later.

After a rather anticlimactic Halloween, my spine noticeably un-tingled, I elected to go see “Saw II,” a movie whose original advertising posters had to be pulled because they were too grisly to pass the Motion Picture Association of America’s approval guidelines.

Last year’s surprise hit horror movie, “Saw,” was remarkable for its tight shooting schedule (18 days) and even tighter budget. Two Australian film students sold the idea for the movie based on an eight-minute short film, and with one directing and one starring, succeeded in making a fiendishly clever and visceral movie, if a somewhat amateur one.

“Saw’s” gimmick was a puzzle, a deadly game where the players had to perform unthinkable acts on themselves or someone else in order to survive. Writer Leigh Whannell and his costar, a beefy Carey Elwes, were chained to the pipes in a filthy bathroom, given several clues and tools and told to kill or be killed within a time limit. Nasty things did indeed happen, but until the heart-stopping climax, the nastiness was delivered via flashbacks of other victims. The two prisoners’ game was mental – a contest of wits, ingenuity and trust.

That’s what worked for the original “Saw.” (That, and some highly inventive ways for people to die.)

The tagline for “Saw II” is “Oh yes, there will be blood.” Viewers who are simply looking for the shock factor in watching people try to escape hideous traps will be satisfied, though for the number of potential victims, the machinations of the killer are few and far between.

This time, the mastermind known as “Jigsaw” from the first movie has kidnapped six lowlifes and set them the task of finding their way out of a decrepit locked house before they die of slow sarin gas inhalation. Syringes filled with antidote are hidden throughout the house, but they’re not easy to procure.

But Jigsaw’s not just a sick wacko – he’s a dying cancer patient who’s dedicated the remainder of his life to testing the survival instinct in human nature. Seems he’s also got an engineering degree, limitless funds and an entire construction crew at his disposal. Pretty impressive for a guy on oxygen and intravenous meds.

The battle of wits in this sequel is far weaker than its predecessor, though fans of the first will be able to tell that screenwriter Whannell gave it a valiant try. (“Saw” director James Wan takes a producer’s seat on the sequel, but the direction by Darren Lynn Bousman isn’t much different.) One of the victims trapped in the house is the son of police detective Donnie Wahlberg, and the face-to-face detente between Jigsaw and Wahlberg is supposed to be the clever mental game that elevates the blood-and-guts game out of slasher land.

Tobin Bell does excel as the creepily rational Jigsaw, but Wahlberg doesn’t take his tormented character anywhere exceptional. As the clock ticks down, viewers care less and less about him and his professed love for his son. The script sticks with the formula from the first plot, even placing the last survivors back in the squalid bathroom from the previous movie, but by this time the stakes are too low for any shock to register.

Nice try, “Saw” guys. You simply fell into the trap of your sizable bank accounts smothering your creative edge.