Harsher in Hindsight: Johnny gets his powers from surviving a serious car accident. This was twenty years before King himself was hit and seriously injured by a van.
The film
Catharsis Factor: While Johnny doesn't manage to assassinate Greg Stillson, the would-be world-destroyer's political future is destroyed forever when a photo of him hiding behind a child circulates, leaving him in an even worse place than if he'd been shot: a living coward and national disgrace, rather than a potential martyr. The book leaves it up in the air what becomes of him afterward — Johnny sees only an absence where his future once was, and whispers "he's in the Dead Zone now" — while the movie changes Johnny's vision to Stillson, bleary-eyed and on the verge of tears, putting a gun under his chin.
Frank Dodd, the Castle Rock Killer, lacks the horrible backstory of his book version. A sadistic pervert who is also secretly the police deputy of Castle Rock, Dodd rapes and murders ten women in the duration of Johnny's coma, sparing not even a 15-year-old girl. He only stops when Johnny Smith's psychic powers out him, at which point Dodd kills himself rather than face justice.
Greg Stillson, despite putting on a front as a man of the people, is in truth an insane sociopath with a dangerous messiah complex. Believing that he's destined to become President of the United States, Stillson decides that nothing will get in his way, leading to him threatening a negative reporter with both blackmail and a death threat. When Johnny views his future, he sees Stillson intentionally launching the country's nukes to kill millions of people despite the news of a diplomatic solution, even threatening to cut off his Attorney General's hand to make it happen, all with a hallelujah on his lips. When Johnny attempts to assassinate him to prevent this, Stillson uses a baby as a Human Shield, showing his true selfish colors to the world.
Martin Sheen as the foaming-mad Midwestern populist President Greg Stillson during the "the missiles are flying! Hallelujah! Hallelujah!" scene is especially funny due to his later role as the idealized East Coast liberal President Josiah Bartlett in The West Wing.
Christopher Walken as an English teacher who tells his class to read The Legend of Sleepy Hollow later plays the Headless Horseman in Sleepy Hollow (1999).
Nightmare Fuel: Frank Dodd's final act is to lower himself onto his own open scissors - stabbing himself to death through the roof of his mouth. Johnny's vision of Stillson forcing the Chairman of the Joint Chiefs of Staff to activate the nuclear football with threats of bodily harm and his eager and ecstatic reaction to giving the final launch order also qualifies.
Playing Against Type: Herbert Lom as the very sympathetic and supportive Dr. Weizak. Although Lom has played his share of dramatic roles throughout his career, at this time and to a whole generation or two, he was mostly famous for his tenure as the long-suffering Da Chief to the Ur-Example of the bumbling detective. This fact alone led many to associate Herbert Lom primarily with comedy and were surprised to see him in such a serious role. Lom clearly having comedic talent of his own, as demonstrated by his portrayal of Commissioner Dreyfuss, makes this misconception understandable if you're not familiar with him from his pre-Panther roles.note : one of which, Phantom of the Opera, he gets to spoof in The Pink Panther Strikes Again
Even in his dramatic roles, Lom usually played villains or various strange, unsympathetic characters.
Tear Jerker: Johnny's interaction with Sarah and her baby are tinged with this, with both of them knowing what they have lost. Both Johnny and Sarah clearly wish that they had been married, and that Denny were their baby. Johnny's father also clearly sees Denny as the grandson he never had.
Woolseyism: As The Legend of Sleepy Hollow was very obscure in France at the timenote even now, the 1999 film (released more than a decade after The Dead Zone) is much better known than the original story, in the French dub the classroom scene doesn't have Johnny teaching a lesson about The Legend of Sleepy Hollow but about Arthur Rimbaud's "Le Dormeur du Val"note "The Sleeper in the Valley", a classic work of French poetry. It also doubles as a sort of Foreshadowing: "Le Dormeur du Val" describes a young man who seems to be sleeping, until the last verses reveals he's dead, and The Dead Zone ends with Johnny's death.
The series
Harsher in Hindsight: In "Descent", Walt is almost killed by a cave-in and tells Johnny to take care of his family, to which Johnny says that's Walt's job and he'll be doing it for a long while. In the season 6 premiere, Walt is actually killed in the fight with Janus, leaving Johnny to take care of the family.
Hilarious in Hindsight: In a Season 2 episode, "Precipitate", Johnny is hit by a car while saving a child. He wakes up in the hospital and asks Bruce if it's 2009 (i.e., if he's been in a coma for ANOTHER six years.) Bruce deadpans "no... it's 2011." Johnny then asks if the Red Sox have won the World Series yet. We now know that in fact they have won it twice in the period Johnny's second coma would have covered, adding an added punch to this joke.
"Valley of the Shadow": Francis Ritter, believing Johnny Smith to be a true prophet of God, undergoes a mission to force him to accept his responsibility. Kidnapping a child and leaving behind no evidence that Johnny can find, Francis leads him and Sheriff Walt Bannerman on a wild goose chase around the city, staying one step ahead of them despite Johnny's abilities the entire time. Almost managing to kill them with a bomb, Francis also predicts their plans to ambush him with a SWAT team, escaping the ambush but leaving behind clues to draw Johnny to his location. Predicting that Johnny would come alone, Francis leaves behind a second clue for Walt, timing it just right to convince Johnny to take his duty as a prophet seriously before he gets himself gunned down by police after one final prayer.
"Ascent": The Guide, heavily implied to be Death itself, is a surprisingly affable entity who seeks the lives of both Walt and Johnny. Having already lost the chance to take Johnny's life once before, the Guide lures him into Walt's consciousness before trapping him there, intending to have them both die at once. Playing the role of Walt's father within his memories and convincing him to Go into the Light. Retaliating against Johnny's changing of Walt's memories with his own mind games, the Guide finally touches Johnny, beginning the process of killing both of them. When Johnny manages to keep resisting, the Guide continues pressuring Walt to give in, only finally ceasing when it becomes clear he's going to lose and silently letting the two of them wake up.
Moment of Awesome: Reverend Purdy finally gets to help Johnny save people in "Cabin Pressure" and he does not mess around, going straight to an Air Marshal and delivering his most passionate sermon yet:
"I have less than fifteen minutes to live, Kelly, is it? I'm not going anywhere. If you wanna handcuff me too, be my guest but you're gonna hear me out. I believe that God had a very specific purpose for putting Johnny Smith aboard this plane. We were supposed to travel on a private jet tonight - it was grounded for repairs. And then we missed our first flight. Call it fate or destiny or God's will, it's no coincidence that Johnny is onboard. It is also God's will that you're onboard this plane, Kelly, cause Johnny can't hope to save all these passengers without your help. The only question is will you accept the role that fate has created for you or will you regret it for the rest of your very short life?"
Paranoia Fuel: Episode 1.08 is horrific in its simplicity. The idea that absolutely everything about your life could simply be a mental fabrication while you're laying in a coma - or, from Sarah's side, your loved one suddenly declaring that everything happening to them isn't real despite all evidence to the contrary - is absolutely terrifying, especially if you're in Johnny's situation where your life is everything you could want and entering the "real" world would destroy it.
Seasonal Rot: The show struggled with creative and financial issues after Season 2.
Due to original showrunner Michael Piller becoming very sick with head and neck cancer, he was unable to lead the show after Season 2 and the plots are noticeably different from Season 3 onward. Rather than Johnny Smith using his psychic powers to prevent terrible events, the show switched to Johnny solving crimes after the fact.
Without Piller to rewrite all scripts, ongoing arcs like the Dana Bright romance, Armageddon, Johnny's celebrity, his security problems were scaled back and then forgotten. Worse, Johnny's powers changed: Piller wrote Johnny as experiencing past and future events from another person's point of view and feeling their emotions. Later writers just had Johnny watch past and future events from a third person point of view.
Johnny's powers also shifted due to budget cuts. The show was originally a UPN project budgeted as a major network show. A new UPN regime decided not to air it. USA Network, a cable channel, picked it up, but they clearly struggled to fund it. Starting with Season 3, Johnny's visions had fewer special effects and less first person experience to save money on facial morphing.
Also due to budget cuts, one actor was laid off in Season 3 and Season 6 laid off another three regulars. Despite these cuts, USA Network cancelled the show after Season 6, citing high production costs.
When Rev. Purdy tearfully lays out for Johnny why Johnny's mother killed herself.
Sarah's breakdown at the end of "Descent"—powered both by Walt being near death and the fact that her chances of coming clean with him and making amends have just plummeted.
"Speak Now" has two: Sarah's reaction to Johnny demanding to know if, had she known he'd wake up, she'd have waited for him (her broken-voiced "How can you ask me that?!" is just heart-wrenching)...and Johnny's vision of her shedding tears over his unconscious form, telling him Walt's asked her to marry him.
The very last scene of the final episode involves Johnny and J.J. skipping stones together, and J.J. almost casually calling Johnny "Dad" for the first time. This also bookended Johnny's original trauma of seeing him call Walt "Dad" back in the very first episodes.
They Changed It, Now It Sucks!: Season 6 shows a lot of changes from the very beginning — ranging from how the Stilson arc is handled to locations and even the absence of the opening narration. Even if you like the last season, the differences are still pretty... weird.
They Wasted a Perfectly Good Plot: The fact that the Season 5 finale gets our blood pumping for an epic showdown between Johnny and Malcolm Janus... which is pathetically quashed when Janus dies in such an anti-climactic way. Even if they wanted to orient the Season 6 premier around Walt dying... they could've still worked that in to the "Epic Final Duel" by having our two heroes fighting Janus heroically and Walt pulling an Heroic Sacrifice to save Johnny. Instead, we got an episode-long Mood Whiplash from what the show had been building up to.
Johnny suffers a LOT of angst from his visions (especially in the intensely tragic "Playing God")... and from the fact that a random accident kept him from all his dreams of a life Happily Married to Sarah.
Sarah constantly suffers from the conflicting emotions of her love for Johnny and her devotion to Walt. And she's put through the emotional ringer in Season 6.
's "Le Dormeur du Val"note , a classic work of French poetry. It also doubles as a sort of Foreshadowing: "Le Dormeur du Val" describes a young man who seems to be sleeping, until the last verses reveals he's dead, and The Dead Zone ends with Johnny's death.