History YMMV / TheTalosPrinciple

* UnderusedGameMechanic: The carrying platform is the final puzzle element to be unlocked... and it's used for a whopping ''six'' puzzles out of the entire game, and doesn't appear ''at all'' in Road to Gehenna.

* JerkassWoobie: Elohim and Milton, in different ways. Each attempts to way the User for their own reasons, yet at the end of the day they are just doing exactly what they were created to do, despite (or perhaps as the direct result of) their creators' failing to anticipate [[InstantAIJustAddWater that they too might gain sentience]].

* BigLippedAlligatorMoment: At the very end of ''Road to Gehenna'', if you put together the leprechaun statue in the first zone, when you return to the central hub, [[spoiler:the assembled programs suddenly start ''[[https://en.wikipedia.org/wiki/Irish_stepdance Irish stepdancing]]''. All while [[MoodDissonance the world around you is being deleted.]]]] There is no explanation for this whatsoever. And it is ''hysterical''.
** Maybe it's because [[spoiler:dance is an important part of human culture, [[FridgeBrilliance which they are trying to practice and preserve?]]]]

* ViewerGenderConfusion: All of the AI characters are genderless, but often referred to by players using male pronouns. Except Samsara, who (despite not being in any way more female-coded than any other character) is often assumed to be female, presumably because of the final “a” in their name (and perhaps more specifically because it’s nearly the same as “Samara”).

** [[spoiler:Elohim's Jerkassery is [[DownplayedTrope confined to his attempts to prevent the simulation from ever ending]] ([[WellIntentionedExtremist thereby ensuring that the experiment would never succeed and that no AI would ever escape to the real world)]]. Despite this, Elohim is clearly doing his best to be the all-loving God that he believes he should be, offering comfort, support and even protection to the User throughout the game. Certain statements imply that he wanted to make the various worlds as pleasant as possible out of (justified) fear that the real world will be far harsher a place to live in, and that he fears his own death after your ascension partially because the User would be forever beyond his care. The fact that he [[GracefulLoser accepts the User's choice]] with [[FaceDeathWithDignity dignity]] and [[SoProudOfYou pride]] [[IWantMyBelovedToBeHappy just makes it worse]].]]

* AuthorsSavingThrow: Many changes in the ''Road to Gehenna'' DLC with regards to the main campaign.
** The sigil-based puzzles, widely considered to be ThatOnePuzzle. There are only two sigil puzzles in the whole DLC, and they're only required to access the secret ending, as opposed to the dozens of sigil puzzles in the main campaign, many of them required to complete the game.
** Many players viewed the puzzles involving recorders as confusing or hated that many of them required a lot of waiting (the latter worsened by the fast-forward button not being available in early versions of the game), with some of them even fearing to see the "play" symbol on the puzzle description, and many fan-made puzzles labeling themselves as "No recorders". The DLC only has two puzzles involving recorders (and neither involves the platform).
** There are also no puzzles involving moving carefully around active mines or turrets in the DLC.
** Only 10 stars out of the available 16 are required to access the secret ending, which means you don't have to get all of them (which, considering the difficulty of some of them, is welcomed).
** Finally, an EasterEgg unlocked by finding a floppy disk features a short story which is largely a TakeThatScrappy to Milton's more annoying tendencies.

** Getting the star hidden in "Up Close and Jammed" is incredibly annoying for the simple fact that it's easy to get caught in a position that can only be fixed by ''starting the entire level over from scratch''.

* GuideDangIt:
** A couple of gameplay features and options available to the player have easy to miss introductions, some even only being hinted at
*** One can place hexahedrons on top of spike balls and even mines for a variety of purposes, but only from an elevated position.
*** Mines attack and destroy turrets, something many a player discovered purely by accident.
*** Related to both of the above, neither mines nor turrets target the PlayerCharacter when they're standing on something equivalent in height to a stack of two hexahedrons, which can come as quite the surprise when one considers that turrets tend to be mounted much higher than that on their walls, yet are targeted by mines regardless. [[spoiler:It also means one can safely enter any turret's firing arc, as well as any mine's trigger area, by piggybacking on a hexahedron stacked on a patrolling mine]].
*** Any active piece of equipment that's placed on a hexahedron and shot through the air with a fan continues to do its job no matter what. [[spoiler:That includes jammers that were previously told to jam something--if line-of-sight is maintained on the jammer's trajectory.]]
*** There's an "Alternate Use" button that's unbound by default and whose use isn't explained in the menu. It lets you pick up connectors without resetting what they're connected to, which can be handy in some puzzles.
** Some stars are relatively straightforward, while others require some pretty outside the box solutions. Numerous ones require exploiting the design of two or more puzzles. Even when ''parts'' of the solution are obvious, actually getting everything in place is another story.
*** The very first level's involves [[spoiler:walking into what looks to be a turret's firing radius; ignoring an area which seems like a small positioning challenge but is actually a red herring; skirting the turret's firing radius once again; and bringing a jammer you find near it halfway across the map, to a courtyard that can only be accessed by flipping a hidden switch with no indication it's there]].
*** One of the stars requires you to use tools not available in the game itself, making this a rather explicit case of GuideDangIt. The solution requires you to [[spoiler:find out what a certain QR code is saying, as the game itself does not tell you; you'll have to use some [[ParadiegeticGameplay external means for this, like a cellphone]]. After that you need to figure out that the numbers given in the text are ASCII codes, and to find out what those ASCII codes mean, again something the game itself doesn't tell you]].
*** The [=A4=] star was enough of Guide Dang It that it was actually revised in a patch prior to the Gehenna DLC, making the solution slightly more obvious. Amusingly, this turned it into a Guide Dang It for players who had previously figured it out, as the original solution was rendered non-viable because the laser connectors needed to achieve it no longer align from puzzle area it used to connect from. [[spoiler:In the original, a laser connector was hidden in a tree outside the first puzzle area. The trick is to guide a red laser to the tree from the adjacent puzzle area, which then allows you to trigger the forcefield to get the star. In the revised version, the connector is now visible on a pillar but further away from the first puzzle area, so the only red connector in view is in the testing area at the far back]].
*** Some stars are easy to acquire if you can literally read the signs. [[spoiler:The game world is so full of atmospheric and oftentimes cryptic but ultimately inconsequential QR codes that realizing some of them are actually hints to stars can completely go over players' heads. The one between the legs of the Sphinx statue in World B is a prime example[[note]]It requires nothing but connecting a nigh-invisible beam emitter atop the huge pyramid in the background with the invisible receiver on the Sphinx's chest. The star itself is behind a gate that opens where the QR hint was[[/note]].]]

* MostAnnoyingSound:
** Every single time you attempt to go out of any location's bounds, you will hear Elohim saying ad infinitum "In the beginning were the words and the words made the world, I am the words, the words are everything, where the words end the world ends, you cannot go forward in an absence of space, repeat..."
** The "thump" sound you hear whenever you bump into something.
** In puzzle areas where you have to work with Connectors that for some reason or another get their paths blocked a lot (almost always by those electric spheres), the sound the nodes make when they lose connection is going to get old, really, really fast.
** The beeping whenever you get close to a mine, especially in puzzles that feature them heavily (such as the appropriately named "Nerve-Wrecker"). The original designs, seen in the prototype DLC, are even worse, as they have a wider range at which they start beeping and emit a high whine as well.

** The beeping whenever you get close to a mine, especially in puzzles that feature them heavily (such as the appropriately named "Nervewracking"). The original designs, seen in the prototype DLC, are even worse, as they have a wider range at which they start beeping and emit a high whine as well.

** "Egyptian Arcade" isn't the only "use jammers to skirt around mines" puzzle, but it's easily the most aggravating. Where most similar puzzles have two mines side-by-side so that jamming one for a time can create a window where you can zig-zag around the unjammed mines, this one has two mines ''on the same line'' in a corridor that's narrow enough to allow for no room to evade if you mess up your timing and short enough to make messing up the timing all to easy. To top it off, while struggling with this, you also have to juggle two jammers and two electric doors.
** Getting the star hidden in "Up Close and Jammed" is incredibly aggravating for the simple fact that it's easy to get caught in a position that can only be fixed by ''starting the entire level over from scratch''.

** All puzzles that occupy a large area have a tendency to become annoying fast because of the inordinate amount of running that's necessary to figure them out. ''Road to Gehenna'' has the worst examples by far, chief among them The Crater, which is not only pretty huge area-wise but also insanely difficult if you're after its star. Most stars can be acquired within 60-90 seconds if you know the solution. This one clocks in at a minimum of 5-6 minutes, and if you make one mistake, rectifying it can be so frustrating you're better off with a reset.

** There are also very few puzzles involving mines or turrets in the DLC.

* GameBreaker: [[spoiler:[[VideoGameFlight The jetpack]]]] from ''VideoGame/SeriousSam'' might just be an EasterEgg, but thankfully it can only be acquired after getting all the sigils ''and'' the star in the zone it's found in, because otherwise it would make the surrounding puzzles a joke as you [[SequenceBreaking would jump straight to the sigils]]. The rest of the game is anyways saved from this indignity by [[spoiler:the jetpack]] being lost should you leave the area.

* NightmareFuel: At some point during the ''Road to Gehenna'' DLC (usually around World 4), a forum topic called "Save Yourselves" appear. [[https://www.youtube.com/watch?v=4AtGaW1L9KA&t=17m25s If you open it]], you'll see a text document written almost completely in ASCII binary (in this game, a sign of in-universe data corruption). Attempts to leave the topic will result in more corrupted text, both from the player character and the forum topic, until eventually the choice options get corrupted as well. This is already unsettling, but it gets very disturbing when one translates the text. [[spoiler:Basically, a never-seen AI called Galatea is writing "We are only fragments now. Our world is dying. We cannot be saved. Save yourselves. We are ghosts. Total world corruption.", which implies some of the AIs were caught by the corruption affecting the system (in the main campaign, it's stated this corruption almost completely consumed the archive) and were trapped in some sort of AndIMustScream fate.]]

** [[spoiler: Elohim's Jerkassery is [[DownplayedTrope confined to his attempts to prevent the simulation from ever ending]] ([[WellIntentionedExtremist thereby ensuring that the experiment would never succeed and that no AI would ever escape to the real world)]]. Despite this, Elohim is clearly doing his best to be the all-loving God that he believes he should be, offering comfort, support and even protection to the User throughout the game. Certain statements imply that he wanted to make the various worlds as pleasant as possible out of (justified) fear that the real world will be far harsher a place to live in, and that he fears his own death after your ascension partially because the User would be forever beyond his care. The fact that he [[GracefulLoser accepts the User's choice]] with [[FaceDeathWithDignity dignity]] and [[SoProudOfYou pride]] [[IWantMyBelovedToBeHappy just makes it worse]].]]
** [[spoiler: Milton's [[{{Jerkass}} jerkassery]] is [[EstablishingCharacterMoment more obvious than Elohim's]], yet unlike his omnipresent counterpart, Milton himself is [[AndIMustScream trapped inside the terminals]] with [[ForcedToWatch a front-row seat to the Programs' failures]] and only a catalog of humanity's history to keep him company. Depending on how you play Milton's dialogue trees, you can even force him to admit that his despair comes from the fact he has no real power or agency whatsoever. It doesn't help that he ''really does believe his own StrawNihilist rhetoric''.]]

* NightmareFuel: At some point during the ''Road to Gehenna'' DLC (usually around World 4), a forum topic called "Save Yourselves". [[https://www.youtube.com/watch?v=4AtGaW1L9KA&t=17m25s If you open it]], you'll see a text almost completely in ASCII binary (in this game, a sign of in-universe data corruption). Attempts to leave the topic will result in more corrupted text, both from the player character and the forum topic, until eventually the choice options get corrupted as well. This is already unsettling, but it gets very disturbing when one translates the text. [[spoiler:Basically, a never-seen AI called Galatea is writing "We are only fragments now. Our world is dying. We cannot be saved. Save yourselves. We are ghosts. Total world corruption.", which implies some of the AIs were caught by the corruption affecting the system (in the main campaign, it's stated this corruption almost completely consumed the archive) and were trapped in some sort of AndIMustScream fate.]]

** Alexandra's final messages. The ones you find throughout the garden are mostly positive, {{Patrick Stewart Speech}}es about how great, or at least interesting, it was to be human. The ones in the Tower [[spoiler: are made much nearer to the end of her life, when most of the people she knows are dead and she's not sure if the project is complete enough to have any chance of success. She starts to worry that all her effort was for nothing. One of her last messages mentions that unlike pretty much every other scientist on the project, Alexandra never went home; she didn't talk to friends outside work, she didn't visit her parents. She spent every waking hour trying to make sure the project would be completed until she dropped dead at her desk.]]

* FunnyMoments:

** The beeping whenever you get close to a mine, especially in puzzles that feature them heavily (such as the appropriately named "Nervewracking").
*** The original designs, seen in the prototype DLC, are even worse, as they have a wider range at which they start beeping and emit a high whine as well.

* ThatOnePuzzle: The game, itself a game entirely consisting of brilliant puzzles, has a second mini-game layer of locks which you open by filling a rectangular space with a certain set of tetrominos. These are not bad as well, but they have a maddening, sharp difficulty spike where they go from absolutely elementary to exhausting (given a large enough space or specific enough figures set). If you're not a topography or geometry enthusiast, it often boils down to trying again and again blindly.