* BaseBreakingCharacter: Grace in [=GK2=] can be this. While many fans find her gameplay more interesting, there are others who can't stand [[{{Tsundere}} her attitude]].
* BestLevelEver: Le Serpent Rouge in Gabriel Knight 3 is regarded as one of the greatest puzzles in the genre.
* CompleteMonster:
** ''Sins of the Fathers'': [[MorallyAmbiguousDoctorate Dr. John]] is the fanatical madman so obsessed with Voodoo culture that he becomes the [[DragonWithAnAgenda second-in-command]] to [[AntiVillain Malia Gedde]] of the demonic spirit Tetelo. Fully organizing the Gedde cult of Voodoo worshippers, John began perpetrating the "Voodoo Murders", a series of vicious killings where the victims' hearts would be ripped out. Along with regularly having anyone who could oust him assassinated, John [[BloodBath bathes in the blood of his kills]], and it is seen that he has numerous other victims in his lair, with piles of skulls, dismembered limbs, and body-less faces abounding. When titular [[TheHero Gabriel Knight]] begins investigating him, John kidnaps the man's assistant, Grace, and plans to use her as the latest sacrifice to Tetelo and the gods of death they worship, with John never showing any form of remorse for his victims or care for Tetelo; just [[PsychoSupporter raving fanaticism]] toward the Voodoo gods of destruction.
** ''The Beast Within'': [[TheDragon Baron Garr von Zell]] was, from the start, a rude, unlikable {{Jerkass}} with nothing but malice toward his fellow man. However once his [[AxCrazy true nature]] is discovered, he quickly becomes one of the most wicked villains in the franchise. Turned into a [[OurWerewolvesAreDifferent werewolf]] by [[BigBad Friedrich von Glower]], von Zell [[SavageWolves became addicted to the thrill of killing]], and quickly began murdering innocents, not for food like all other werewolves, but just ForTheEvulz. In these "mutilation killings", von Zell ravenously shreds more than half a dozen innocents to pieces, one of whom was a [[WouldHurtAChild little girl]], and he plans to continue his spree after [[FrameUp framing a pair of wolves for the killings]], later murdering a man who tries to blackmail him with the fact that he is the true killer. While Gabriel and [[EvenEvilHasStandards von Glower]], disgusted by von Zell's wanton {{sadis|t}}m, manage to stop him before he kills too many more, von Zell makes sure to turn Gabriel himself into a werewolf before his death to screw with him one final time. A psychopath with nothing driving him but base impulses of hate and cruelty, Garr von Zell was without a doubt the most evil werewolf Gabriel encountered.
** ''Blood of the Sacred, Blood of the Damned'': [[AGodAmI Excelsior Montreaux]], real name Sanae, was once an adamant follower of Jesus Christ, but after growing jealous of his master, attempted to drain him of his blood to gain his godly powers. Though driven off by other followers of Christ, Montreaux began hunting down Christ's descendants then draining them of their blood as they slept, leaving them deathly sick for weeks to pass before repeating the process over and over again, which inevitably lead to his victims' deaths. Feasting on the blood of these descendants, [[OurVampiresAreDifferent sparking the legend of the vampire in the process]], Montreaux has kept himself and his followers alive for over 2,000 years, and, alongside executing any who get to close to the truth of his Satanic {{cult}}, Montreaux plans to murder the latest descendant of Christ, [[WouldHurtAChild the infant Charlie]], drink his blood, then use the power it will give him to lead his cult in taking over the world. The final, and perhaps most evil, villain Gabriel faced, Montreaux truly cared for no one or no thing but himself and his {{immortality|Immorality}}.
* ContestedSequel: Gabriel Knight 3
* [[CrowningMusicOfAwesome Crowning Soundtrack of Awesome]]: Among Sierra's best, including an entire libretto written for ''The Beast Within''.
* EnsembleDarkhorse:
** Grace is arguably more popular than the titular character. The character has her own page on Wiki/TheOtherWiki while Gabriel doesn't, is PromotedToPlayable in the sequels, and people generally find her parts of [=GK2=] and 3 to be more interesting than Gabriel's.
** Friedrich von Glower is fairly popular with the fans, to the point where he [[spoiler:appears in ''Temptation'' comic.]]
* FirstInstallmentWins: Whilst [[BrokenBase opinion is divided]] as to whether GK 2 or 3 was the worse sequel, it is agreed neither hold a candle to the original.
* FoeYay: [[spoiler:Gabriel and Von Glower]] -- very intentionally too.
* FridgeBrilliance: Novelisations of the first two games were released, but never the third. In-universe, Gabriel writes two Blake Backlash novels based on the cases he encounters in ''Sins of the Fathers'' and ''The Beast Within'', but it's implied that between his depression over Grace leaving him and his full-on breakdown as of ''Temptation'' that he never got around to writing a novel based on his experiences in ''Blood of the Sacred, Blood of the Damned''. Hence no novelisation of that game, perhaps?
* FridgeHorror: In GK 2, Leber tells Gabriel an account of a runaway teenage girl who was seen going into the forest before being taken by a large [[spoiler: black]] wolf. Considering the girl's reported beauty and the killer's identity [[spoiler: with the forest very close to a certain hunting lodge]], it's entirely possible the victim did not enter the forest randomly [[spoiler: but was instead seduced into a meeting and betrayed with a horrific revelation]].
* GameBreaker: Deducing the correct combination to the old clock found in Grandma's attic, while essentially logical, is arguably one of the hardest puzzles in the entire series, due to the fact that the hints provided by the game will most likely seem to most gamers as totally unrelated. There is, however, an effective, albeit tedious and boring way to solve it without consulting a game guide, namely to try out every single of the ''1728'' possibilities. The game designers seem to have thought about such an approach, which is probably why the correct symbol to match the hands of the clock to is located [[spoiler:immediately to the left from the default symbol, thus causing most gamers, naturally prone to going through the puzzle the way a normal clock hand would move, to waste hours on end of their gameplay, finally getting the right combination at the very end of their torment.]] It doesn't help that every time you move the hands of the clock, the cursor will automatically teleport to the very fringe of the screen and possibly make you accidentally turn off the puzzle, forcing you to go through the annoying icon-changing sequences every five minutes or so.
* HarsherInHindsight: In ''Sins of the Fathers'', it's possible to have a conversation with the gravedigger where he outlines in graphic detail what would happen to the bodies buried in New Orleans if there was a flood, twelve years before Hurricane Katrina.
** An in-universe example, probably deliberately played up in the 20th anniversary remake, where it's far more pronounced. If Gabriel continues to bug Grace for his messages after she's read them all for him, she'll exclaim in mock melodramatic exasperation "I've given you everything I have!" Funny enough, but if you've played the whole original trilogy and know how their relationship ends up taking its toll on Grace, it's an uncomfortable bit of {{Foreshadowing}} on her part.
** While there are certainly extenuating circumstances, the scene at the end of [=GK1=] where Mosely guns down Dr. John is much more unsettling in light of the recent PoliceBrutality against black civilians in the US.
* HilariousInHindsight: In [=GK3=], Larry Chester is writing a manuscript he hopes will introduce [[spoiler: the fact Jesus has descendents]] to mainstream society. He tells Gabe it'll come to light in the next decade. Out of universe, about four years after the game, [[spoiler: Literature/TheDaVinciCode]], a book featuring the same pseudo-history, became a best seller.
* HoYay: plenty in ''The Beast Within''. Specifically, [[spoiler: von Glower's past lovers include Ludwig and von Zell, and he's [[http://www.youtube.com/watch?v=8Us4_nKLd1g&t=3m44s clearly]] interested in Gabriel as well.]]
* LesYay: It's pretty strongly hinted that Lily and Estelle in ''Blood of the Sacred...'' are more than just "companions".
* MagnificentBastard: [[spoiler: Von Glower]] in the second game.
* MostWonderfulSound: In the first game, a small piano tune appears whenever you pick some items or solve puzzles.
* NightmareFuel: In the first game,[[spoiler:Wolfgang tears his own heart out so Gabriel can get the Schattenjäger amulet.]] It also doubles as a TearJerker moment.
* NeverLiveItDown. The cat moustache puzzle in [=GK3=]. To this day, many adventure game-related articles such as the infamous [[http://www.oldmanmurray.com/features/77.html rant from Old Man Murray]] tend to use that puzzle as one of the main examples why adventure genre died.
* OohMeAccentsSlipping: Curry actually does a fairly convincing Southern-American accent about 99% of the time, but every once in awhile you'll hear a critical fail that wasn't redone.
** NarmCharm: This actually is probably the only "bad" voice acting in the game, sans the Narrator. When it fails, it's an EpicFail but that's what adds to the charm.
** Curry repeatedly pronounces "New Orleans" as "New Orleens", which is obviously something a true New Orleanian (or someone who's watched ''Series/{{Treme}}'') would never do. One of the few directorial changes to voice acting in the 20th anniversary remake is to have Gabriel pronounce it "N'Awlins"
** The German accents throughout ''The Beast Within'' are generally pretty good -- until Grace talks to the workman installing the chandelier in the game's final act. He says "ja" a couple of times, and says the rest of his lines in a normal American accent.
* ParanoiaFuel: In ''Sins of the Fathers'' once you find out about the Rada Codes. Then you notice the drummers stationed all over the city. You know, the ones you've probably been ignoring because they just sit there all day and drum. [[spoiler:They're not only watching you, they're broadcasting your moves to the creepy voodoo cartel that's already left a number of messy corpses all over the city.]] And of course, the creepy looking guy who just stands outside the shop for two days and stares in the window.
** If you listen in on the drummer on the day after you crash the St. John's Eve conclave, the only word you can make out is "Warn." YMMV, of course, on whether it makes the Paranoia Fuel better or worse that the frightful Voodoo cult is just as frightened of ''you.''
* RewatchBonus: Plenty of minor incidents in [=GK3=] after you learn that [[spoiler: Emilio is an immortal]].
* SeriesHiatus: Despite the story for the fourth installment being written in time for teasers to be included in ''Blood of the Sacred'', poor sales and a lukewarm reception led to a lack of funding that meant there hasn't been a new Gabriel Knight game since 1999. However, [[WordOfGod Jane Jensen]] has never stopped expressing her interest in continuing the series when and if she's able to, and with the series' increasing CultClassic status and the moderate surge in interest generated by the 20th anniversary in 2013-14, there's hope yet.
* SlowPacedBeginning: The series suffers from this for those not interested in backstory, historical minutiae, and/or drawn-out interview processes, especially when controlling Grace. Each of the three games takes about half the game for the action to pick up, which is good when it does, but until then it's jarring.
* SpecialEffectFailure: The Beast Within, when it comes to the Werewolves. They are completely computer generated and looked awful(but not in the intended way) when the game was released. The fact that the Normal wolves are depicted via video footage of actual wolves makes the werewolves look even worse by comparison. The damage is limited by the fact the wolf-form werewolves get relatively little screen time until the end.
* TearJerker: [[spoiler: Wolfgang's HeroicSacrifice]] in the first game.
* ThatOnePuzzle:
** In the first game, translating and writing a message in the cemetery certainly does a mention.
** Not very many puzzles require even rudimentary knowledge of any language besides English, so even with the in-game German-English dictionary telling you all the German words you need to know, the "Drei Drachen" puzzle counts too.
** The cat moustache puzzle, as stated above.
** Some players have trouble with the audio splicing puzzle early in the second game. This is mitigated a little in that, unlike the voodoo message puzzle in the first game, once Gabe gets a word correct, you're unable to remove it from the splice.
* TheyChangedItNowItSucks: Many fans aren't happy with the results in the first game's remake.
* UncannyValley: The character models in [=GK3=] looked awkward and have not aged well even during the game's initial release.
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