Complete Monster: Unlike the criminally insane original, the stepfather in the 2009 remake is a narcissist, who murders families he joins when they fail to meet his expectations. Already having killed at least two previous families, including their young children, the stepfather seduces single mother, Susan Harding and becomes engaged to her. Killing anyone who delves into his past to keep up his façade, the stepfather murders Susan's elderly neighbor, her ex-husband and her sister. After Susan's eldest son, Michael, discovers the stepfather's murderous past, he declares the Harding family has failed him and tries to kill them all before moving on.
Jerkass Woobie: The stepfather, in the original at least. The remake averts it.
The "Who Am I Here?" scene in the remake is extremely funnier when he goes after the dumbass who just pieces together that he was a murderer after being told repeatedly about his suspiciousness.
Rooting for the Empire: At least in the original and in Stepfather II. Terry O'Quinn's charming and likable performance can make the viewer forget that his character is a crazed serial killer. The Cinema Snob even pointed that out in his reviews of both films.
They Wasted a Perfectly Good Character: All that build and anticipation towards the final confrontation between The Stepfather and Jim Ogilvie has an anti-climatic payoff with The Stepfather just instantly killing him and Jim is all but forgotten in the next scene. The Cinema Snob pointed out how pointless all that build-up was since the confrontation didn't make the character important to the plot.
What an Idiot!: Susan in the remake, big time! You'd expect her to notice something's off with her fiance when the warning signs came up, as obvious as a blaring alarm, but nope. She just swats them off. It's to the point where you'd want her to die.