[[quoteright:310:http://static.tvtropes.org/pmwiki/pub/images/Yu-Gi-Oh_-_Forbidden_Memories-PS1-Gameplay-screenshot-1_3513.jpg]]

''Yu-Gi-Oh! Forbidden Memories'' is a Yu-Gi-Oh! video game for the UsefulNotes/PlayStation. The game takes place in both modern times and Ancient Egypt, and the player character switches accordingly. Throughout most of the game, the protagonist is Atem, the Prince of Ancient Egypt. However, after the high priest Heishin overthrows the Pharaoh, he sets out to free Egypt from Heishin's tyranny and is accidentally transported to modern times.

The game serves as an AlternateUniverse to the manga and anime, with the BigBad being a different person, and many of Yugi's TrueCompanions making appearances as characters in Ancient Egypt. For all practical purposes, it can be seen as an early draft of the Ancient Egypt arc that had yet to start in the canon media at the time. It has two sequels, ''VideoGame/YuGiOhTheDuelistsOfTheRoses'' and ''VideoGame/YuGiOhTheFalseboundKingdom''.

The game was one of a few that were released before the trading card game was, and as such, uses prototype rules that were originally considered for the TCG. Major differences include no tributes being necessary to summon level five and higher monsters, all monster cards being normal monster cards, only one card being placed on the field each turn, fusion being done without the card Polymerization, and the majority of the possible fusions not being actual fusions in the TCG. The game is additionally poorly balanced, with the vast majority of cards being monster cards, and the few magic and trap cards having simple effects that are [[UselessUsefulSpell usually not useful]], while the ones that ''are'' useful are nearly required to beat the game.

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!This game provides examples of:

* AdamSmithHatesYourGuts: Want those powerful cards without cheating or dueling specific characters? Hope you're prepared to fight hundreds upon hundreds of duels to get the Star Chips required to buy even a single card. The max amount of Star Chips you can get winning a duel is five, where any decent or useful card will cost hundreds or thousands of Star Chips. To make it more ridiculous, many cards cost 999,999 Star Chips, some of which you can't win from dueling.
* AdaptedOut: Since the game was made before Battle City and the Ancient Egypt arcs were finalized, Marik and Thief King Bakura don't appear.
* AdaptationPersonalityChange: Due to the game being released before Battle City came out, Ishizu/Isis and Priest Seto are majorly different than their manga and anime counterparts.
* AdaptationalVillainy: This version of Priest Seto rivals Death-T era Kaiba in terms of villainy and pettiness. Among other things, he served as Heishin's right-hand man and was responsible for seizing all of Egypt, kidnapped Teana as a hostage to lure you into a deadly Shadow Game, was fine with the murders of the Prince's parents and enacted Heishin's order to seal the tombs, preventing the Prince from seeing his parents' bodies, and was descended from evil sorcerers and plans to renew a pact with [=DarkNite=] in order to rule the world. His stated reason for doing all this? He's of noble blood and you're not, therefore he deserves to rule.
* AllThereInTheManual: The manual contains a letter from Pegasus J. Crawford explaining that the game is based on an archaeological find.
* AndIMustScream: [[spoiler: After spending the entire game collecting the Millennium Items to summon [=DarkNite=], Heishin is turned into a card at the end. It isn't very long because [=DarkNite=] then burns the card.]]
* AnimationBump: When attacking an opposing monster with your own, by pressing the square button, you can view a 3D battle sequence between the monsters. Some of the more popular/noteworthy monsters had higher quality and more detailed models; compare the models of the [[http://4.bp.blogspot.com/-EvAQLdICses/UO7K1-SD5JI/AAAAAAAAAJg/3Ya9luTUPNo/s1600/Imagem1.png Blue-Eyes White Dragon]] and [[http://3.bp.blogspot.com/-4EUzNEoeqfU/UO7hsMNA3qI/AAAAAAAAAK0/kMzUivHZVXk/s1600/Imagem9.png Red-Eyes Black Dragon]] to the models of [[http://1.bp.blogspot.com/-XS8uqsmcCS4/UO7hcAnmKGI/AAAAAAAAAKs/1Il-I1dfvVY/s1600/Imagem8.png Tiger Axe]] and [[http://3.bp.blogspot.com/-1MJBIMU5urw/UO7vQRuUy-I/AAAAAAAAAMk/fo0wuiQnE_w/s1600/Imagem16.png Dragon Zombie]] for example.
* ArbitraryHeadcountLimit: Your deck must have exactly 40 cards, no more, no less.
* ArtificialStupidity: The AI in this game has several flaws.
** If you have a face-up monster on your side of the field while the AI has no monsters, they will always play a single monster card, regardless of the situation. This can be exploited to ensure your opponent does not fuse on you, does not equip their monsters, and prevents them from using magic/trap cards. The exception to this is the low field mages, who will always use the magic card to change the field type to match their specialty if it's in their hand and the field is currently something else, even if doing so means that they will be left with no monsters to defend themselves.
** They will never put a monster of 3000 or higher base attack in defense mode, regardless of how strong your monsters are and how much their monster has been weakened, as well as regardless of if the battle damage would result in their defeat. On the inverse, some monsters that have much higher defense than attack will never be attacked with, even if attacking with them would win the duel for the AI.
** If the AI's monsters are not strong enough to destroy any monsters on your field, they'll always switch them to defense (the exception being 3000+ monsters). They'll even do this if the monster of yours they're unable to destroy has the same attack as the strongest monster on their field, while having lower defense.
** The AI will also always switch their monsters into defense when they're bluffed into not attacking your facedown monster, regardless of their monsters' defense values (unless it's a 3000+ attack monster). This can be exploited to defeat high attack, low defense monsters that you would be unable to destroy otherwise.
* AwesomeButImpractical:
** Ritual cards can be used to summon very powerful monsters you otherwise wouldn't have access to without cheating, with an extravagant animation for the summoning process. However, each ritual card requires three specific monsters on your field to work (which is usually a GuideDangIt to know what the required monsters are for each ritual), and most of these required monsters are too weak to keep alive long enough without significant magic/trap assistance. The ritual monsters themselves are also usually not that much more powerful than more conventionally obtained monsters or are even weaker. Rituals overall are too inflexible and time-consuming to be utilized in a practical manner, while fusion and equipping work much more effectively and faster for getting stronger monsters out.
** A lot of trap and non-equip magic cards, since you can only play one card per turn. A lot of the time, the turn you use to place a trap or magic card could have been better used setting up a powerful monster to deter the A.I. from attacking, which is especially true if the A.I. currently has more monsters on the field. While their are some exceptions, if you're doing well enough that you can set them on the field, you likely could have won without them regardless. This does ''not'' apply in the end game, where the opponents' monsters will greatly outweigh anything you can legitimately get. You ''will'' need those cards for that part of the game.
* BigNo: The final boss lets out one that ''fills two text boxes''.
* BossGame: What Forbidden Memories essentially is.
* BossInMookClothing: Villager 2 doesn't even get a name, but he will likely serve you your first loss due to having powerful cards and fusions for that point in the game. If you're really unlucky, he can fuse a Twin-Headed Thunder Dragon.
* BonusBoss: Several opponents in the game are completely optional to duel (with the early game consisting almost entirely of optional opponents), who defeating won't give you anything additional other than another opponent to duel in Free Duel.
** Simon Muran, who you can duel if you return to the palace before you attend the festival.
** Jono and Teana, as well as Villagers 1, 2, and 3, who you can duel in the dueling ground.
** Seto 1, who you can duel if you attend the festival with Teana.
** When you return to the past, you can duel Jono and Teana 2 in the hidden dueling ground, as well as again duel against Villagers 1 and 2 (though 3 will now refuse to duel you).
** Seto 2, who you can duel if you traverse the labyrinth to rescue Teana after her capture, but before defeating all the high mages (if you do this after defeating the high mages, you go to the end game instead). This bonus boss is notable as it's the only one that rewards you beyond what you gain from a normal duel victory (in this case, it makes the endgame slightly shorter and easier by allowing you to skip dueling the Labyrinth Mage in the final boss rush).
* BossRush: The end game requires you to duel and defeat seven straight opponents, with no chance to retreat and save in between. If you successfully traverse the labyrinth after Teana is captured to rescue her, before defeating all the high mages however, and defeat [[BonusBoss Seto 2]], you'll skip the Labyrinth Mage in the endgame gauntlet, making it slightly easier.
* ButThouMust: There are a few instances in the Campaign where you're given a "choice" on what action to take in a confrontation, but the game requires you to pick a specific option to progress the story and not choosing it will just result in a character prodding you to pick that required choice until you do it. Averted with the initial choice to sneak out and enjoy the festival. You can just give up when Simon catches you and skip the first act of the game.
* ChangingGameplayPriorities: Early on, the game favors getting powerful beatsticks out early, as well as quickly fusing into more powerful beatsticks such as [[InfinityMinusOneSword Twinheaded Thunder Dragon]] to overpower your opponent. Once you get to the end of Kaiba's tournament, the game will require a good balance of both power and magic in order to get past the mid-game. Once you get to the end game gantlet, though, expect to be playing a ''very'' defense oriented deck, often with a lot of traps to easily take out your opponents' beatsticks that vastly outclass anything you could reasonably summon.
* CoversAlwaysLie: Hey look the Pharaoh is holding up a Magician of Black Chaos, sure would be nice to get that card in the American version. Too bad it was for the Pocket Station only.
* CrutchCharacter: Pretty much all the fusions besides the [[DiscOneNuke Twin-Headed Thunder Dragon]] and [[InfinityPlusOneSword Meteor Black Dragon]] fusions, in particular the Mystical Sand, Flame Cerberus, and to a lesser extent, Crimson Sunbird fusions. Mystical Sand (2100 attack) is made from the fusion of any female and rock monster, while the Flame Cerberus (2100 attack) is made from any beast and fire-alignment monster, and Crimson Sunbird (2300 attack) from any winged-beast and fire-alignment monster with one having at least 1300 attack. They begin tapering off in the finals of Kaiba's tournament, become only useful as a supplemental force against the mages, and fusing for them will be a waste of space in the endgame.
* DamselInDistress: After you beat two of the high mages, Heishin has Teana kidnapped and brought to his shrine, to lure the prince and his Millennium Puzzle into his clutches. When you choose to go rescue her is up to you, though waiting until after you beat all the high mages will make the endgame slightly more difficult and make [[BonusBoss Seto 2]] LostForever.
* DevelopersForesight: You ''can'' beat Heishin at the very beginning of the game with a legitimate deck. Heishin muses "Not bad, boy," but then [[ButThouMust reduels you until you lose to him.]]
* DifficultySpike: The early game starts out easy, with you being presented with opponents that all can be defeated reliably without any grinding, outside [[HopelessBossFight Heishin]]. Then comes Kaiba's tournament in the present, where each of your opponents rapidly get stronger and more difficult. And the game [[NintendoHard never lets up from here on out]].
** And then there's the [[BossRush Boss Rush]] in the endgame, with six or seven straight duels with no save point. With monsters like Blue-Eyes Ultimate Dragon and traps like Widespread Ruin likely to screw you over no matter how good your deck is, this part of the game can easily be considered RNG Hell.
* DiscOneFinalBoss: Kaiba, who is the final opponent in his tournament and thus the final opponent in the present arc. He's also the first opponent you have to beat that has a high chance of using a monster with 3000 attack, and he has his own unique battle music.
* DiscOneNuke: The Twin-Headed Thunder Dragon fusion. To create one, all that is required is any Dragon type monster and any Thunder type monster, with one of them having an attack of 1600 or higher. The Twin-Head has an attack of 2800 and is compatible with two field cards, as well as compatible with a variety of equip cards, making it easy to power up. With proper deck building around it, the Twin-Head can be reliably used to take on any monster outside of the Blue Eyes Ultimate Dragon, and carry the player to the end game.
* DistressedDude: [[spoiler:After you beat Seto for the final time to stop him from taking the Millennium Items to resurrect [=DarkNite=], Heishin takes Seto hostage by holding a knife to his throat, in demand for the items.]]
* DittoFighter: In Free Duel, there's an opponent named Duel Master K that's available from the start, and is never seen in the campaign mode. His deck is a copy of the player's deck. Generally seen as being there to teach players the possible fusions and combinations in their deck, as his card drops are terrible beyond early game standards.
* DummiedOut: The original Japanese release of the game was compatible with the Pocket Station, with features that allowed players to obtain cards that otherwise could never be won from dueling. Since the Pocket Station was never released outside Japan, international releases of the game had the Pocket Station compatibility and features removed. This rendered the cards that can not be won from dueling to be unobtainable in international releases of the game without using a cheat device.
* EarlyBirdBoss: Weevil Underwood is the second opponent the player faces in Kaiba's tournament, as well as the third mandatory opponent. While the player could coast through the early game and [[WarmupBoss Rex Raptor]] with their starter deck, Weevil is a step up from Rex, and unless the player has a solid grasp on fusions and did some grinding to improve their deck, they are likely to get stomped by him. Once the player learns how to play and to adequately grind, Weevil will fall easily, though having provided a [[NintendoHard taste on what is to come]].
* EarlyInstallmentWeirdness: Gameplay wise, the rules of dueling are quite different from what they later became. No tributing is needed to summon any monster card, fusions don't require a magic card to fuse and most fusions have general requirements rather than specific monsters, only one card can be played on the field at a time, you draw until you have five cards in your hand and you cannot skip a turn without playing a card, and there are several monsters that are ritual monsters in the game that aren't ritual monsters in the card game.
** Storywise, Seto is a far different character, and the sealing of the Pharaoh happens completely differently than what later became canon. Also since this was made before the official appearance of Ishizu and Marik, there is a slight change where Ishizu becomes Isis and is a completely different character from her Battle City appearance, while Marik doesn't appear at all, and the Millennium Rod has been given to Kaiba.
** The cards in the game will also be this to non-Japanese players, as many of the cards were really early cards released in the OCG that didn't get released outside Japan until many years later, or in the case of some, still never been officially released, thus international players are unlikely to recognize much of the game's card library. Even the game's famed Meteor Black Dragon didn't get officially released outside Japan until 2012, 12 years after the game's Japanese release and 10 years after its localization.
* ElementalRockPaperScissors: Each monster can be given one of two alignments available to it, with each alignment being strong against one other alignment, while being weak to another. When a monster fights a monster with an alignment its strong against, it'll temporarily gain 500 attack and defense points for that battle. The alignments go Sun (Light) -> Moon (Fiend) -> Venus (Dreams) -> Mercury (Shadow) -> Sun, and Mars (Fire) -> Jupiter (Forest) -> Saturn (Wind) -> Uranus (Earth) -> Pluto (Thunder) -> Neptune (Water) -> Mars.
* EnigmaticMinion: Seto isn't happy serving under Heishin, but he's not friendly to the player, either. Teana and Jono note that he seems to have his own agenda, and it's revealed that [[spoiler:he planned to backstab Heishin and take over himself]].
* EverythingIsTryingToKillYou: Lose one duel in story mode, even against your friends, and it's game over. The only exception is the HopelessBossFight against Heishin.
* EvilIsPetty: Seto's stated reason for doing horrible things in an attempt to rule the world is because he's of noble blood and you're not, and therefore he's the only one fit to rule.
* {{Expy}}: Jono and Teana ''are'' Ancient Egyptian Joey and Tea.
* FinalBossPreview: What the HopelessBossFight against the game's BigBad Heishin in the beginning of the game essentially is, showing you the kind of deck strength you're going to have to overcome at the end to beat the game.
* ForcedLevelGrinding: Once you're in the present in Kaiba's tournament, if you don't take advantage of Free Duel to get new cards to strengthen your deck, don't expect to get far past [[WarmupBoss Rex Raptor]] without significant luck, as your starter deck will be far too underpowered to do much against the quickly escalating opponents. Grinding can be alleviated a bit though, through [[SaveScumming Start Scumming]] to get a better starter deck, Start Scumming with a second file to get cards to trade over to the first file, and by knowing which opponents to grind against.
* GameMod: There are several mods of this game that alter the drop lists, mainly to make card drops more balanced and sensible for the opponent, as well as making the unobtainable cards from the original winnable. The same person who created some of these mods also created a ''Forbidden Memories 2'' mod, an unofficial sequel that replaced many of the cards in the game with new ones, as well as a new story and several other alterations.
* TheGhost: The Prince's parents are mentioned, but never seen.
* GuideDangIt: The game has several examples of this:
** The exact monsters required for each ritual card. While the description of each ritual card typically gives you a hint on what is required, these hints are vague, and often don't cover all three monsters needed to complete the ritual; some ritual cards don't even give you any hints on any of the required monsters at all.
** The possible fusions in the game. Most are simple enough to reasonably figure out on your own through some trial and error, and the fusions requiring specific monsters are intuitive (such as Black Skull Dragon), as well as can be learned from following the anime and playing the card game. Fusions can also be learned by watching what the computer fuses. The fusions requiring magic cards on the other hand...
** S-Tec-ing. One would think it would mean using a lot of magic and trap cards yourself. While that's part of it, the most reliable way is exploiting that A.I. into fusing so they have less overall cards than you, and then stalling until they run out of cards. Without a guide, how is one even supposed to know how to exploit the A.I.? This is especially true for [[TheAllSeeingAI Pegasus]], who gives out some of the best magic and traps in the game.
** The cards you can win from each opponent. While sometimes intuitive, they are nonsensical other times, such as being able to obtain a [[InfinityPlusOneSword Meteor Black Dragon]] from the Meadow Mage.
** The fact that many cards can not be legitimately obtained in the game without unrealistic grinding to 999,999 starchips (such as Summoned Skull), or unable to be obtained at all.
** The correct path to traverse the labyrinth when rescuing Teana, which is [[spoiler: right, right, left, right]]. While it isn't too complicated for one to reasonably figure out on their own, there is no indication that you encounter the Labyrinth Mage if you go the wrong path instead of the right path, and there's no indication that going the wrong path brings you back to the beginning.
*** The Teana capture quest in general and subsequent Seto 2 duel. It happens after you beat two high mages, but you're not informed it happens unless you go back to the dueling ground before defeating all the high mages. Additionally, if you beat all the high mages before saving Teana, going through this quest will advance straight to the endgame instead of the Seto 2 duel, leaving Seto 2 LostForever for Free Duel on that file until you beat it and start a NewGamePlus.
** When you beat the game, you're given a password at the end of the credits. You're given no information on what this password does, and it does not work if you try inputting it into the game. It's a password for its sequel, ''VideoGame/YuGiOhTheDuelistsOfTheRoses''.
* HaveANiceDeath: Losing to an opponent in story mode will have them comment on your defeat.
* HearingVoices: Kaiba claims to hear the Millennium Rod whispering for him to defeat Yugi. Given who originally owned the Rod, it's likely Priest Seto was guiding his descendant.
* HelloInsertNameHere: Although you are the Pharaoh, this was made before his name was revealed in canon.
* HopelessBossFight: The first time you duel Heishin, where he'll be using endgame-caliber cards while you still have your starter deck. If you defeat him, he'll rematch you until you lose. This is also the only duel in Campaign that you are allowed to lose.
* HostageForMacGuffin: Near the end of the game, Heishin holds Seto in a headlock, puts a dagger to his throat, and forces you to hand over the Millennium Items so he can perform an evil ritual. Despite the fact that [[spoiler:Seto was in the middle of performing the ritual himself until Heishin interfered]], you have to do as he says.
* ImpossibleItemDrop: The Meadow Mage, seemingly just another low-level mook before a high mage, inexplicably gives you the best card drops out of anyone in the game. The only way people have beaten the game is by grinding against him for cards.
* InfinityMinusOneSword: For equip cards, there's Bright Castle, which can be used to power up ''any'' monster's stats by 500 points.
* InfinityPlusOneSword: The Meteor Black Dragon is the strongest monster card the player can obtain without cheating, with 3500 attack. While it doesn't have much equip versatility, it has the best possible alignments, with Mars allowing it to take out the Ultimate Great Moth without an equip, and Sun allowing it to take out the Gate Guardian without an equip, leaving the Blue-Eyes Ultimate Dragon and another Meteor Black Dragon as the only monsters it can't beat without equips. You can obtain it from defeating the Meadow Mage, a rather easy opponent you can fight right after you win Kaiba's tournament and go back to the past.
** For equip cards, there's Megamorph. Not only is it able to power up any monster in the game, but it strengthens their attack and defense by 1000 points (while every other equip only powers up by 500).
* InfinityPlusOneElement: Dragons are the game's most powerful monsters on average, having high attack and a variety of alignments. They additionally have better fusion capabilities than every other type. This means dragons will be extremely valuable right from the beginning, and will be the player's main attacking force throughout the game. They also tend to have [[AnimationBump much better 3D models]] in the 3D battle sequences. Their few downsides are a lack of equipment variety and a weakness to Dragon Capture Jar.
* InstantWinCondition: There exist two alternative methods to winning a duel, that will automatically win the duel for the player.
** The opponent not having enough cards in their deck to draw a full hand of five cards. Since the player always goes first, the only way for the player to win by this method would be to exploit the AI into doing more fusion/card combining than themselves. Winning in this manner results in an automatic S-Tec.
** A player having all five pieces of Exodia in their hand. It is impossible to win this way without cheating, since Exodia's legs cannot be won and cost 999,999 starchips each. A few of the opponents have access to all the Exodia pieces, but it is extremely rare for them to use all of them and get them all in their hand to win this way.
* JackassGenie: [=DarkNite=] is supposedly bound to obey the owner of all seven Millennium Items. He is summoned by the tribute of all seven Millennium Items - which means the summoner doesn't have them anymore. He also refuses to obey those who haven't made a contract with him.
* LastLousyPoint: There are several obscure cards in the game that are not that useful, but have incredibly low drop rates, and are usually obtainable from only a single specific opponent that you won't duel often because of their poor/mediocre card drops. Unless you have the original Japanese version and a Pocket Station, there are many other cards that you cannot legitimately obtain.
* {{Leitmotif}}: Priest Seto and Seto Kaiba get remixes of the same theme, which is used when they appear and when they duel you.
* LostForever: The optional opponents have a specific timeframe in which you can duel them, and if you progress in Campaign beyond this timeframe, you'll be unable to go back and duel them for the rest of the Campaign.
** Simon Muran, who you'll be no longer able to duel if you don't run away from his lecture in the beginning scene or don't go back to the palace before going to the festival, as those events will trigger the early game's ending sequence.
** Teana 1, Jono 1, Seto 1, and Villager 3, if you return to the palace to initiate the ending sequence of the early game before going to the dueling ground and through the festival subplot to duel them all. Villagers 1 and 2 will become reavailable when you return to the past however.
** Teana 2 and Jono 2, once you beat all the high mages, regardless of if you did it before saving Teana after her capture. If you did it before saving her, going to the dueling ground automatically initiates you going to the labyrinth to save her, which then automatically goes to the endgame sequence if you beaten all the high mages at that point. If you did it after saving Teana, talking to them will just give you words of encouragement with no option to duel them. Villagers 1 and 2 will also become permanently unavailable at this point if you didn't duel them already.
** Seto 2 will become permanently unavailable if you don't rescue Teana before beating all the high mages, as you'll go straight to the endgame sequence instead of dueling him.
* MissingSecret: There are many cards in the game that you see opponents use, that have the impossible 999,999 starchip cost to buy, and that you just never seem to win from dueling. These cards are not among the drop lists for any opponent in the game, and you were intended to obtain these cards through features from playing on a Pocket Station. Since the Pocket Station was [[NoExportForYou never released outside Japan]], these features were removed altogether in international releases and are impossible to obtain without cheating.
* NewGamePlus: When you clear campaign mode, you are able to keep playing through it again, with no difference, other than you being able to run through the entire game with an endgame deck.
* NintendoHard: Since this game was made a few years before the actual card game was released, the game is extremely unbalanced. Additionally, the deck strength of your opponents scale rapidly once you progress past the early game, the opponents will have access to many powerful cards you'll never legitimately be able to use, and you will need to grind a lot, often to just defeat the next opponent in the story, and especially to be able to survive the endgame.
* OneWingedAngel: [[spoiler:After beating [=DarkNite=], he'll transform into [=NiteMare=] and rematch the player, this time with a monster-only deck with all the strongest monsters in the game.]]
** ClippedWingAngel: [[spoiler:As [=NiteMare=], he has no magic, trap, or equip cards in his deck, meaning once you have a monster stronger than the strongest one he has, you'll have the duel won regardless of how badly you were getting beaten.]]
* OpeningTheSandbox: Once the Present Day arc is completed, you can fight the rebellious priests in any order.
* OrcusOnHisThrone: While Heishin was very proactive in the beginning of the game conquering Egypt, gathering the Millennium Items, and overthrowing the Pharaoh, he becomes this once you return to the past, leaving the Prince alone to beat all the high mages and recollect the Millennium items at his leisure. Even when Heishin comes in direct confrontation with the Prince after he traverses the labyrinth to save Teana, he just returns to his shrine and leaves Seto to deal with the Prince.
* PeninsulaOfPowerLeveling: The Meadow Mage is the game's most notorious example, dropping many especially powerful cards at shockingly high rates, including the Meteor Black Dragon as previously covered. '''Everyone''' who beat the game did so after some really extensive grinding against him.
** [[HopelessBossFight Heishin]] becomes available in Free Duel after you duel him in Campaign, meaning you'll have access to him early in the game. He has the second best card drops in the game after the Meadow Mage and drops many endgame-caliber cards that the Meadow Mage doesn't. As soon as the player's deck gets good enough to start getting wins against Heishin, he becomes a very valuable grinding target.
** Pegasus when S-Tecing him; during S/A Tec ranked duels, he drops Widespread Ruin, [[InfinityMinusOneSword Bright Castle]], and most importantly, [[InfinityPlusOneSword Megamorph]]. He additionally drops the latter two at a higher rate than anyone else, especially Megamorph.
* ProductionForeshadowing: Upon beating the game you're given one of several random passwords depending on the name you put for the file, which does not work in Forbidden Memories. The passwords are for ''VideoGame/YuGiOhTheDuelistsOfTheRoses'', where they're used to unlock powerful, game breaking cards.
* RandomDrop: Every time you win a duel, you are given one card, from the drop list of the opponent you defeated. What you did in the duel will decide which cards you can get, with getting a S/A Pow rating giving you access to getting the strongest monster cards the opponent can drop, S/A Tec rating giving you access to getting the strongest magic cards the opponent can drop, and getting anything else will give you access to a mix of cards that are less effective overall.
* RareRandomDrop: Some cards have ridiculously low drop rates in the game and only drop from one or two opponents. Unless you're particularly lucky, you will have to duel the opponent who drops them hundreds or even over a thousand times just to get a single copy of the card.
* RuleOfThree: You can only bring at maximum 3 copies of the same card in your deck.
* ShoutOut: As a nod to its electric attacks in the anime, Summoned Skull's possible guardian stars are Moon (Dark) and Pluto (Thunder).
* TheBattleDidntCount: Heishin will continue to duel you into submission if you somehow manage to beat him in the start of the game.
* TheComputerIsACheatingBastard: Some opponents (Pegasus, Heishin, [[spoiler: [=Seto 3=], and [=Darknite/Nitemare=]]]) are able to read what cards you have face down on the field, and thus can't be bluffed into not attacking your weaker monster/bluffed into attacking your stronger monster. Your opponents also have complete access to the cards you cannot legitimately obtain, and can morph cards they draw into other cards in their deck.
* TheUnfought: In the present day tournament arc, Joey enters the tournament alongside you and remarks about his desire to duel you in the finals of it. Throughout various points of the arc, Joey and Tea mention how he is still alive in the tournament, all the way up to the semi-finals, building up to him being your final opponent. Kaiba however is your opponent in the grand finals instead, having presumably [[KilledOffscreen defeated Joey on the other side of the semi-finals]], after which Joey is never seen nor mentioned again without you ever dueling him. Tea and Ryou Bakura in the present day are also never dueled despite you dueling their past and Yami counterparts respectively, though neither had the buildup Joey had.
* UselessUsefulSpell: The majority of the magic and trap cards in the game have effects that are of situational usefulness, or are just not useful enough to spend a turn using in lieu of playing a monster card.
* WakeUpCallBoss: Pegasus, who is the seventh opponent in Kaiba's tournament, dueled in the quarterfinals. He is a significant step up from prior opponents, with powerful magic/trap cards, good equips, monsters with 2000+ attack, and the capability to create powerful fusions. He is also the only opponent not in the endgame to be able to see your facedown cards, and if the player is unlucky, he may even play a Meteor Black Dragon. He is likely to be the first serious roadblock in a player's progress, and if it hasn't been done already, will drive it in to the player that grinding is an absolute necessity in this game, as well as knowing what you're doing when playing.
* WarmupBoss: Rex Raptor, who is the first opponent you duel in Kaiba's tournament, and the second mandatory duel overall (the first being [[HopelessBossFight Heishin]]). His cards are even weaker than some of the people you dueled in the early game, and he can be reliably defeated with an unmodified starter deck. Considering the difficulty spike that occurs after him, new players can expect to play him a lot in free duel as they learn the game and gain new cards (especially if they skipped the early game).
* XanatosGambit: Priest Seto enacts one that spans the whole game. He serves Heishin faithfully at first, seizing control of the palace and Egypt as a whole. When the prince returns from the future, however, he goes behind Heishin's back and gives hints about how to overthrow him. His plan is to gain the Millennium Items that Heishin's Mages guard, use the Items to renew a pact with [=DarkNite=], and rule the world--which he only tells you ''after'' you collect the Items, defeat Heishin and do his work for him. If the prince failed in his quest, Seto would defeat Heishin and take over himself. If he succeeded in defeating Heishin, he'd take the Items from the prince instead. The only thing Seto ''didn't'' count on was losing his duel with the prince [[spoiler:and Heishin having seen his treachery coming and staging his defeat]].
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