These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Badass Decay: Freddy never joined the good guys (who would want him?) and always was a serious threat to them, but as the series went on, he became quite the jokester, and became goofier and more playful with people's dream sequences than he was in the first few films. This came to a head in Freddy's Dead, where he turned someone's dream into a Nintendo game, where you can tell he's having a great time.
Complete Monster: Freddy Krueger, the dream-invading serial killer antagonist of the franchise. "Bastard-Son-Of-A-Hundred-Maniacs" should probably clue you in. He was a child killer before, he became a ghost, and kept a scrapbook of the "Have you seen this..." pictures of his child victims and licked them. After his death he makes a deal with demonic forces to literally become, in his own words, "the stuff nightmares are made of". He uses his newfound powers to find increasingly creative ways to torture and murder his dozens of victims for his own amusement by using their primal fears against them, all the while cracking really sick jokes. Then he harvests the teenagers' souls and keeps them in a perpetual And I Must Scream state inside his body to drain them for energy. Less so as the sequels went on, when he became a bit of a buffoon too Faux Affably Evil for his own good — though even in the utterly Narm-filledFreddy's Dead: The Final Nightmare, he had his moments, such as when he taunts Tracy by appearing as her sexually abusive father ("Give daddy some honey...no one has to know...") Freddy is one of the few Slasher Movie killers with a distinct and talkative personality, and has always simply been a sadistic monster who extends his victims' suffering for its own sake.
Draco in Leather Pants: Believe it or not, Freddy has an extraordinarily high amount of fangirls. The fandom likes to portray him as a woobie whose terrible past and upbringing were responsible for his psychosis, and that his love for his daughter was genuine enough to push him off the deep end when she was taken away from him. The fact that Robert Englund has said on multiple occasions that Freddy represents neglect doesn't help this image either.
Misaimed Fandom: It is truly disturbing how many 12 year old girls on deviantART draw cutesy anime-esue fan art about him falling in love with their Distaff Counterpart OC of him they made. Who knew skinless demonically powered child rapists are so "cute"?
Nightmare Retardant: The whole concept becomes significantly less scary when you remember that Freddy only kills in one suburb (a fictional one at that), though it does get worse in Freddy's Dead, in which he states that "every town has an Elm Street" and makes clear that he's planning to expand his reach to the whole world.
As the original series goes on, Freddy's burned skin goes from horrfying to looking like a mild skin condition.
Physical combat isn't Freddy's forte, as whenever he tries to go up-close-and-personal with his victims, he loses. Freddy vs. Jasonaverts this by making him able to have an even fight with Jason.
Paranoia Fuel: The premise alone qualifies, obviously. It's one thing when you fall off a cliff in your dreams and wake up safe at home seconds later. But it's completely different when that can cross over into the real world''.
Sequelitis: Outside of primarily Dream Warriors and New Nightmare, every one of the sequels receives a sizeable amount of dislike.
Villain Sue: From about the third film onwards, Freddy was pretty much undefeatable except when he chose to be. It got to a point where audiences met Freddy's Dead: The Final Nightmare with total cynicism (note how hard the title has to work to establish that he's really going to die in this movie).
Alice Johnson. Has all her friends and her brother killed by Freddy the first time out. Convinced she had him beat, he instead comes back and kills her boyfriend/father of her child, then he sets his sights on corrupting and possessing her unborn child? Life is not good to her. What's worse, all those deaths happen as an indirect result of her own dream power.
Demonic Spiders: Freddy™ himself was likely intended to be this, being able to pop up randomly in the dream world, but with the right Dream Warrior power he's really no harder to deal with than anything else.
That One Boss: Not so much in the final boss fight though when he actually has a health bar and no obstructive terrain, and he litters the floor with those ground-slasher hands as the fight goes on. There won't be any safe places to stand if you can't finish him off quickly.
Hilarious in Hindsight: The color of Freddy's glove on the title screen is the same as his other hand, and looks more organic than usual. It almost seems like a precursor to the look of the claws utilized in Wes Craven's New Nightmare.
Narm: The NES game's insistence of adding a ™ whenever Freddy™ is mentioned.
Not helped by hatred of a similar system used in Castlevania II, the dream world mechanic wasn't well-received due to how poorly it was thought out. To clarify, once you find a Dream Warrior power in the stage, you can easily charge through any enemy with it and thus eliminating the threat of being sent there in the first place. They aren't overly hard to find either, since all the stages are linear. If you somehow don't get a Dream Warrior power before falling asleep (or just finding one in the dream world) however, then God help you. Even if you do get through all the mooks, the bosses well readily end you.
The bone collecting gimmick is hit-and-miss. The houses (stages) that open up in the game are randomized with each separate play-through (though the bosses or not), and not every house that opens will have bones. If you don't see a number other than zero on the bone counter (it counts how many are left to find in the stage, not how many you have), then you have to fight your way through a pointless level for nothing. This can eat up your lives and continues like candy if you're not careful. Thankfully, bosses don't appear in non-bone levels. Made more frustrating as stages that didn't have bones before could have them later after you find the actual bone level and beat it...