* AlternateCharacterInterpretation: The main monster is an [[ItCanThink intelligent]] octopoid, but exactly how intelligent (and thus, its capacity for evil) is up for debate. Some have [[https://horrorflora.com/2021/10/31/fan-ichf-octalus/ theorized]] that Octalus is as malevolent as the ''Indominus rex'', specifically hunting Finnegan and his allies at the end to ''hurt'' them as payback for frustrating its attempts to eat them. Its face-to-face confrontation with Finnegan very much comes across as an act of EvilGloating.
* SugarWiki/AwesomeMusic: While Music/JerryGoldsmith's entire score is excellent, one of the standouts is his kick-ass [[https://www.youtube.com/watch?v=CMAgPQL7jQo Hang On/End Title]].
* BaseBreakingCharacter: Joey, who depending on who you ask, is either one of the most relatable characters with how hilariously out of place he is in the movie, or an irritating [[TheLoad burden]] who contributes nothing to the film.
* CultClassic: The film may have been a flop upon theatrical release, but over the years it has garnered a cult following amongst Sommers fans for being considered as arguably one of his best works and the most DarkerAndEdgier entry of his directing career due to its R-rated nature of gore, profanity and violence (blending with the usual Sommers adventurous wit) in contrast to his more memorable PG-13 rated works ''Film/TheMummyTrilogy'', ''Film/VanHelsing'' and ''Film/GIJoeTheRiseOfCobra'' and his earlier Disney works ''Literature/AdventuresOfHuckleberryFinn'' and ''Film/{{The Jungle Book|1994}}'' (until his R-rated entry ''Film/OddThomas'').
* EvilIsCool:
** The mercenaries, due to their wisecracking and battle-hardened badass characterizations, their VillainousValour and their guns. Finnegan can qualify too depending on his role as a technical VillainProtagonist even if he's a PunchClockVillain himself.
** Octalus itself is a powerful, whale-eating SeaMonster with an ''incredibly'' unnerving design that is actually [[ItCanThink quite intelligent]], even recognizing Finnegan as its ArchEnemy.
* {{Fanon}}: The three remaining heroes are stranded on [[Franchise/KingKong Skull Island]] after surviving their ordeal on the ''Argonautica''.
* HilariousInHindsight: You really have to wonder if the final scene was the major inspiration for ''Series/{{Lost}}''.
* ItWasHisSled: The fact that the "worm" monsters are really just the limbs of one giant octopus-like monster was kept hidden until the end, but pretty much any horror fan who watches it nowadays is aware of this from the get go.
* OneSceneWonder: That one scene where the poor lady tries to hide in the bathroom from the creature, only for it to suck her down through the toilet. Some Youtubers who've seen this movie when they were younger have claimed to not have gone into a bathroom for while ''because'' of that scene.
* RetroactiveRecognition: The film features a huge number of subsequently well-known character actors, and this was one of their earliest projects. This includes [[Series/FearTheWalkingDead Cliff Curtis]], Creator/KevinJOConnor (a year before his StarMakingRole in another Stephen Sommers film, ''Film/TheMummy1999''), Creator/JasonFlemyng and Creator/DjimonHounsou. The film could very easily come off as having an AllStarCast if one was familiar with all of the actor's subsequent filmographies.
* SoBadItsGood: One of the main reasons of its CultClassic status: the film is so unapologetically bent on cool action and gory monsters that it throws every ounce of sense off the window in the process. In his [[https://www.youtube.com/watch?v=0v0gWJUuRaA review]], WebVideo/AndoniGarrido explains how much absurdity the film entails, yet only after stating he loves it.
-->"This movie doesn't deserve to be so unknown. It should be placed among the best shit movies in the history of film."
* SpecialEffectsFailure:
** The creatures do look very good for the time, but whenever they're about to appear for an attack, it's quite obvious the actors are standing in front of a blue-screen for the effects work. This hurts several attacks that were clearly meant to be a surprise.
** When the two leads escape the boat on the jet ski. They're obviously in front of a blue screen. The fact that their ''hair'' isn't moving (as if blowing in the wind) is what gives it away.
** The death animation for the creature looks like LudicrousGibs from a video game.
* TakeThatScrappy: Sometimes, you can't blame the mercenaries around the first act of the film mercilessly subjecting Joey to a NoHoldsBarredBeatdown after [[HeKnowsTooMuch stumbling upon their secret torpedo]], Trillian treating him like crap for no reason after she's just met him or [[spoiler:[[DirtyCoward Hanover]] shooting him in the leg to save his own skin from the monster]], considering Joey being mostly irritating and does nothing to help or further the plot.
* TheyWastedAPerfectlyGoodCharacter: [[spoiler: T. Ray, Mamooli and Vivo (played by Creator/DjimonHounsou), who were killed just moments after they boarded the ship before the main action sets for the rest of the characters. Likewise, Leyla isn't given much characterization outside of being Joey's girlfriend before meting her end.]]
* TooBleakStoppedCaring: While the BigBad is a sea monster, this is a film that has little in the way of "proper" heroes or heroines. Finnegan and his crew seem mostly decent sorts, but are hired for villainous reasons and willingly admit they're OnlyInItForTheMoney. Trillian despite her affableness is a thief who is prone to violence (she breaks Joey's nose within seconds of meeting him and tried to murder her ex-boyfriend in the past). Canton is a fraudster who has no problem abandoning his cohorts to their fates to save himself. The mercenaries are simply mercenaries, if with camaraderie amongst themselves, and the few crew members to survive the initial attack don't last long enough to do anything heroic.
* TooCoolToLive: [[spoiler:The mercenaries are maybe mercenaries, but they put up a heck of a fight against the monster before falling victim to it one by one.]]
* SugarWiki/VisualEffectsOfAwesome: The creature itself was designed by Rob Bottin (''Film/TheHowling'', ''Film/TheThing1982'') with CGI by [[Creator/IndustrialLightAndMagic ILM]] and Creator/DreamQuestImages. There's also a scene with [[spoiler: a half-digested Billy]] by Creator/BlurStudio.
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