[[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 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 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 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.

The game is noteworthy for [[EarlyInstallmentWeirdness using gameplay rules vastly different from the actual card game]]. The game was released before the trading card game was, and as such, uses prototype rules that were originally considered for the TCG. Major differences include no tribute being necessary to summon level five and higher monsters, all monster cards being normal monster cards (thus no monster effects and the such), only one card being able be to 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 (and vice versa). 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 few that are useful like [[OneHitPolykill Raigeki]] verge on being [[GameBreaker Game Breakers]]). Magic/trap cards are made less effective by the one card per turn limit, so if you decide to play/place a magic/trap card, you won't be able to play a monster that turn and thus not strengthen your forces or leave yourself open to a direct attack from your opponent if you have no monsters on the field. This causes the most prominent strategy to be just getting stronger monsters out than your opponent, while strengthening them via fusions and equip cards (thus being a major departure from the prominent strategies in the TCG).

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!This game provides examples of:

* AdamSmithHatesYourGuts: Want those powerful cards without cheating or just dueling a character to get it? Hope you're prepared to fight hundreds upon hundreds of duels to get the Starchips required to buy even a single card. To elaborate, the max amount of starchips you can get winning a duel is five, where any decent or useful card will cost hundreds or thousands of starchips. To make it more ridiculous, many cards inexplicably cost 999,999 starchips (which is pretty much the majority of monster cards with 2000+ attack, those with significance in the anime at the time of the game's release, and even cards that you are incapable of winning from beating people). It's to the point where you would be surprised when a card is actually viable near the endgame and can be realistically bought without cheating.
* AndIMustScream: [[spoiler: After Spending the entire game collecting the Millennium items to summon [=DarkNite=], Heishin is turned into a Card at the end. The Must Scream Moment isn't very long because [=DarkNite=] then burns the card.]]
* ArbitraryHeadcountLimit: You must have exactly 40 cards in your deck, 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 (the exception to this are the field mages, who'll play their respective field card regardless of what you have on your field, even if it would leave them unprotected from a direct attack that will finish them), regardless of if their monster is too weak and a magic card in their hand could wipe out all of their opponent's monsters, there exists a fusion in their hand, or if they have a equip they could combine with their monster to strengthen it enough to defeat your monsters. This can be exploited to ensure your opponent does not fuse on you, does not equip their monsters, and prevent them from using magic/trap cards.
** 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 weaken, 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 the aforementioned 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 (thus allowing your monster to safely destroy their equal in attack monster).
** 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. This can be exploited to defeat high attack, low defense monsters (such as Summoned Skull and Jirai Gumo), that you would be unable to destroy otherwise.
* AwesomeButImpractical: Rituals are too convoluted, difficult, and time consuming to actually utilise, while offering too little of reward to be worth it, especially when there exists vastly superior options for creating stronger monsters (such as the aforementioned Twin Head fusion and just equipping monsters). You're better off using the minimum deck space of four cards that would be needed to use a ritual (which is one tenth of your deck) on other cards. Also, some other cards which have been banned from the modern TCG variants for their versatility, have limited usefulness under this ruleset. Dark Hole, which destroys every monster on the field, is now an invitation for your opponent to hit you directly with his next summon, because of the 1 card per turn rule.
* BossGame: What Forbidden Memories essentially is.
* 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 Teena, 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 Teena.
** When you return to the past, you can duel Jono and Teena 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 Teena 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 (all seven being difficult opponents by themselves, and the last four of which are the most difficult opponents in the game), with no chance to retreat and save in between (meaning if you lose to any of them, you must duel them all over again). If you successfully traverse the labyrinth after Teena 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 very slightly easier (though this doesn't help much, as the opponents to come are vastly more difficult).
* 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]].
* DiscOneFinalBoss: Kaiba, who was the final opponent in his tournament, as well as the final opponent you dueled in the present time. He was also the first opponent you have to beat that has a high chance of using a monster with 3000 attack (prior opponents Pegasus and Isis could play the Meteor Black Dragon and Black Skull Dragon respectively, though it was very rare for them to), and he was the only opponent to have his own unique battle music.
* DiscOneNuke: The Twin Headed Thunder Dragon fusion. To create one, all that is required is any Dragon type monster (which includes pseudo dragons such as Dragon Zombie), and any Thunder type monster, with one of them having an attack of 1600 or higher (such ingredients can be in the deck you start out with, and aren't difficult to obtain in the early/mid game). The Twin Head has an attack of 2800 (which only 10 monsters in the game have an higher attack than, and is strong enough to wipe out your opponent's life points in just three direct attacks), and is compatible with two field cards (being a Thunder type, it is powered up by sea and mountain, and is the strongest monster with a dual compatibility), as well as compatible with a variety of equip cards, making it easy to powerup. With proper deck building around it, The Twin Head can be reliably used to take on any monster outside the Blue Eyes Ultimate Dragon, and reliably carry the player to the end game. Eventually, unless you're fortunate enough to obtain Sanga of the Thunder, the Thunder monsters required for your fusion will become unviable for use themselves (and have poor fusion prospects outside the Twin Head), and the Twin Head becomes overshadowed by the obtainable [[InfinityPlusOneSword Meteor Black Dragon]] (and to a lesser extent, by the slightly weaker but even more equip versatile Skull Knight). Regardless, a card of the Twin Head is actually reasonably obtainable, and remains very viable in the end game.
* DistressedDude: Heishin kidnaps Seto by holding a knife to his throat.
* 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 mirror 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 (such as, no tributing is needed to summon any monster card, fusions don't require a magic card to fuse and specific monsters aren't always necessary, 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 becomes 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.
* 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.
* EverythingIsTryingToKillYou: Lose one duel in story mode (even against your friends), and it's game over; the only exception is the HopelessBossFight against Heishin.
* EnigmaticMinion: Seto
* {{Expy}}: Jono and Teena ''are'' Ancient Egyptian Joey and Tea.
* 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 with the few additional cards you win from the optional duels in the early game, will be far too underpowered to do much against the quickly escalating opponents. Do expect to grind a lot in Free Duel before you can defeat the next opponent in campaign, and you will need to do an extreme amount of grinding if you're to have any hope of [[NintendoHard surviving the endgame]]. 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 (such as useful equips and multiple Raigekis), and by knowing which opponents to grind against (dueling [[MoneySpider Meadow Mage]] a hundred times for example, will give you much better rewards than dueling Kaiba one hundred times).
* GameMod: There exists a mod of this game that alters the drop lists, mainly to make card drops more balanced and sensible for the opponent (such as, you no longer win Meteor Black Dragon from the Meadow Mage, with all the field mages giving cards pertaining to the types they use, and some non early game opponents, such as Teana 2, who were useless to duel before, now having worthwhile card drops), as well as making the unobtainable cards from the original winnable (albeit, they're extremely rare to win). The same person who created this mod also planned to create a Forbidden Memories 2 mod, an unofficial sequel that replaced many of the cards in the game with new ones, as well as several other alterations. However, [[DevelopmentHell the creator did not meet promised dates to release things pertaining to the mod (such as a beta and trailers), and nothing has been heard about it from the creator in over a year]].
* GuideDangIt: The game has several examples of this:
** The exact monsters required for each ritual card. While the description of each ritual card gives you a hint on what is required, these hints are commonly vague, and often don't cover all three monsters needed to complete the ritual.
** 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...
** The fact that getting a power or technical rating when winning a duel affects the card you win (getting a power ranking gives you a chance to win more powerful monster cards, while a technical rating gives you a chance to win more useful magic and trap cards). Exactly how to obtain a technical ranking instead of a power ranking is never explained by the game or its manual.
** The cards you can win from each opponent. While sometimes intuitive (such as being able to obtain a Red Eyes Black Dragon from Jono 2), 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 Teena (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.
* HelloInsertNameHere: Although you are the Pharoah, this was made before his name was revealed in canon.
* HopelessBossFight: The first time you duel Heishin, you'll duel him at the end of the early game, where your monsters still have stats in the hundreds or a little over one thousand, while he has endgame monsters with attack power exceeding 3000, along with powerful magic/trap cards and Megamorph. You must lose this duel to progress in the story, as if you defeat him (which while pretty much impossible when not on a [[NewGamePlus new game plus]] without extreme luck and the Twin Head fusion), he'll rematch you until you lose. This is also the only duel in Campaign that you are allowed to lose (losing elsewhere results in a Game Over).
* ImpossibleItemDrop: The Meadow Mage, seemingly just another low-level mook before a high mage, that specialises in warrior type monsters and associated cards, would be assumed to give you warrior-related cards that are slightly better than mediocre at best. However, he instead inexplicably gives you the best card drops out of anyone in the game. Such cards include several monsters with 1800+ attack (including Meteor Dragon, a strong dragon that can be used to easily fused for the Twin-Headed Dragon and Meteor Black Dragon), Curse of Dragon (2000 attack and can be used as a strong ingredient for the Twin-Headed Thunder Dragon fusion, as well as fused with Gaia to create the Dragon Champion), Gaia the Fierce Knight (2300 attack with good equip versatility and has the useful Mercury alignment), Dark Magician (2500 attack, with also good equip versatility and the Mercury alignment), Skull Knight (2650 attack, with the Mercury alignment and the best equip versatility in the game), and the '''[[InfinityPlusOneSword Meteor Black Dragon]]'''. While these cards can be obtained from other, harder opponents, they have a much higher drop rate from the Meadow Mage, especially Skull Knight (where the Meadow Mage is five more times likely to drop it than the few other opponents who can). Once you defeat him in campaign, run off and grind against him in Free Duel. You're going to need those Meteor Black Dragons and Skull Knights to complete the game.
* InfinityMinusOneSword: For equip cards, there's Bright Castle, which while it strengthens monsters by 500 points like any other equip, can be used to power up any monster (whereas other equips have a limited pool of monsters they can be used on).
* InfinityPlusOneSword: The Meteor Black Dragon can be seen as this. It is by far the strongest monster card the player can obtain without cheating, with 3500 attack, which is tied with the Perfectly Ultimate Great Moth for 3rd highest in the game, and 500 points higher than the next strongest obtainable monsters, the Blue Eyes White Dragon and Metal Zoa. While it doesn't have much equip versatility (only being powered up by Dragon Treasure and Salamandra outside the universal equips, which is still one more than nearly every other high level dragon is capable of being powered up by), it has the best possible alignments, with Mars allowing it to take out the aforementioned Ultimate Moth without an equip, and Sun allowing it to take out even the Gate Guardian without an equip. Obtaining it however, is actually not that difficult, as 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 (which is the halfway point in the game), and the card itself is not all that rare (you can reasonably obtain a Meteor Black Dragon by the time you defeat the [[ImpossibleItemDrop Meadow Mage]] around 50 times or so). Compare this to the second strongest obtainable cards, Metal Zoa, who can only be obtained as a very rare prize from Sebek (who you can only grind against in Free Duel after completing the game), and Blue Eyes White Dragon, who can only be obtained as a rare prize from [[spoiler:Seto 3]] (who like Sebek, can only be fought in Free Duel after completing the game, and is the [[ThatOneBoss most difficult opponent to defeat as well]]). This is very fortunate for the player, as the Meteor Black Dragon is pretty much required for the player to [[NintendoHard reliably get through the end game without significant luck]].
** 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 (every other equip strengthens by 500).
* InstantWinCondition: There exist two alternative methods to winning a duel, that should occur, will automatically win the duel for the player, regardless of the cards on the field and the remaining life points.
** 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.
** A player having all five pieces of Exodia in their hand. [[spoiler: It is impossible to win this way, since Exodia's legs cannot be won and cost 999,999 starchips each. A few of your opponents can, though this is extremely rare.]]
* JackassGenie: [[BigBad 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!
* 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 (such as Dungeon Worm from the Labyrinth Mage and Hourglass of Courage from Jono). Those striving to [[OneHundredPercentCompletion obtain every card in the game]] must then duel these neglected opponents extensively (possibly in excess of 1000 duels) to win just one of these lousy cards. This is all for naught though, as unless you have the original Japanese version and a Pocket Station, there are many other cards that you cannot legitimately obtain. Not that this hasn't stopped people from trying to find some way to win them without cheating for years, leading to [[UrbanLegendOfZelda several theories on how to win them and false claims of winning these cards]].
* 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. Turns out, these cards are not among the drop lists for any opponent in the game, and that 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 since the developers didn't adjust the drop rates of opponents to accommodate for this, these cards are not legitimately obtainable without using a cheating device (or actually grinding up to 999,999 starchips, which people have calculated would take ''years of nonstop playing to reach'', which you then would only be able to buy one of these cards anyway unless you utilise a copy file and trade exploit with three memory cards).
* 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 (Was Released in US shortly after Duel Monsters was Localized and following the card game as well), 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.
* RandomDrop: Every time you win a duel, you are given one card, from the drop list of the opponent you defeated. How well 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, where 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 card. And since most of these cards are not that good, they'll just bring the player closer to OneHundredPercentCompletion unless they were fortunate enough to obtain one of these less useful cards early on. Fortunately for those looking to collect every card, a lot of these cards can be reasonably bought with star chips, and the weaker ones can even be found in starter decks.
* TheBattleDidntCount: Heishin will continue to duel you into submission if you somehow manage to beat him in the start of the game. Why? [[GenreSavvy Because it's a card game and he has no reason to back down when he's beaten, unlike you who was cornered and have no means to defend yourself from his Millennium Rod's Magic which has just incapacitated your guardian.]]
* 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 (such as ritual monsters, Black Skull Dragon, Shadow Spell, etc.), and can morph cards they draw into other cards in their deck (which often leads to them having multiples of the strongest monster in their deck on their first turn).
* UrbanLegendOfZelda: There are many cards in the game that cannot be won from dueling. Naturally, there have been people who have claimed to have won these cards, usually in combination with claiming to having won it through having an extraordinary amount of wins against a specific opponent, as well as dueling a specific, convoluted way. All of these claims were never verified, with their video/screenshot proof always being debunked. Eventually, a group of players hacked the game, and found that indeed, these cards are not in the drop list for any opponent. Even with this proof to confirm these cards as unobtainable, it hasn't stopped people from claiming to have won them or believing they can be won through some way.
* 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 (particularly the Crimson Sunbird and Twin Headed Thunder Dragon). 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 (though fortunately it is very rare for him to have it in his deck). 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. The opponents to come provide similar difficulty, keeping him from being ThatOneBoss.
* 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).