Mutually Exclusive Power-Ups

Choose wisely.

The case in video games where picking up one weapon or powerup results in losing another. This makes control schemes simpler, but may be more annoying. This is particularly aggravating if the game allows you to increase the level of a weapon or powerup only to lose it later. In some scenarios, if the player is required to possess a certain powerup to proceed, other powerups must be avoided at all costs, or else the player will have to backtrack to a previous area to swap for the correct one.

More merciful games allow the player to merely "drop" the old weapon rather than it simply vanishing into nothingness, allowing the player to easily swap between them (like an Inventory Management Puzzle with a limit of one weapon).

This trope doesn't apply to cases that involve explicitly choosing or trading between two weapons (like the choice of three starters in the Pokémon games).

Compare Inventory Management Puzzle, Limited Loadout, Stance System and Swiss-Army Hero. Sub-Trope of Discard and Draw and Uniqueness Rule. See also Mutually Exclusive Magic.

Contrast All Your Powers Combined.

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Examples:

Action Game

• You cannot have both piercing bombs (which penetrate walls) and remote control bombs in Bomberman, with the exception of the first Super Bomberman game. The bomb kick and walk over bomb powerups are also mutually exclusive.
• Contra:
  • In the NES version of the first game and its sequel Super C, the bullet speeds of all of your weapons can be increased with the "Rapid Bullets" power-up. However, this upgrade is lost when the player changes to another weapon. This doesn't apply to the arcade version of the first game, in which the increased bullet speed is carried over from one weapon to another until the player loses a life due to the rarity of the Rapid Bullets power-up in that version.
  • In the arcade version of Super Contra, as well as Contra 4 for the DS, all of the weapons in the game can be upgraded once by picking the same power-up twice in a row. However, the extra firepower is lost when the player picks up a different weapon.
  • In Contra Advance, the GBA version of Contra III: The Alien Wars, the player drops his previous weapon whenever he picks up a new one, allowing him to revert back to his previous weapon if the new one is not to his liking, much like in the post-Dracula X Castlevania games. This was mainly added to make up for the lack of dual wielding in the GBA port.
• Duke Nukem II. Duke can only carry one special weapon: (L)aser, (F)lame Thrower, or (R)ocket Launcher. Picking up a different weapon replaced the current one. Worse, there's also the infrequent (N) powerup, which returns you to Duke's default gun.
• Gunstar Heroes lets players carry two of its four weapon types at a time, which can be used individually or combined into a special weapon.
• Picking up a special weapon in Metal Slug would replace the current weapon. A couple later games allow the player to hold one weapon in reserve, though.
  • You also can only have one type of bomb (normal or stones) and also only one type of shell for any Slug.
• The NES/Famicon Ninja Gaiden series. For the third game they let you see what the item was before you broke the sphere it was stored in, making it easier to avoid picking up an item you didn't want by mistake.
• The haircuts in Rocky Rodent.

Adventure

• The hats of Kid Chameleon.
• King's Quest: Mask of Eternity has a limit of one short-range weapon (dagger/axe/sword) and one long-range weapon (bow/crossbow). When you pick up the new weapon you drop the old one. Leave and come back, and the old weapon is still there, in an aversion of Everything Fades. However, there isn't really any functional difference between the different short- and long-range weapons except for their strength — except the warhammer, which takes an annoyingly long time to swing.
• Skyrim: The werewolf and vampire lord forms are very powerful, but you're prohibited from wearing any equipment (with the exception of a few very specific rings) and cannot cast spells (with the exception of a few specific spells for the vampire lord). Since the right equipment can make you extremely powerful (particularly if you exploit enchanting to make gamebreaker gear), this can render the transformations massive letdowns.

Action Adventure

• In the Castlevania games up to and including Harmony of Dissonance, you can only carry one subweapon at a time. In the games before Rondo of Blood, the subweapon you had before disappears. From Rondo on, you drop the previous subweapon onto the ground, and can pick it up again in the event you change your mind about changing weapons, or picked up the new one by accident. Also, in games where the Double Shot and Triple Shot items exist, you automatically lose these if you change subweapons. Sometimes just getting these items in the first place means that you have to stick with one subweapon for an extended period of time.
• Subverted in Control: The Board only gives you access to one powerup in The Foundation DLC: You have to choose between the ability to psychically grow crystal formations ("Self") or to destroy them with your gun ("Weapon"). However, you are later given the other power by an entity called FORMER. The Board isn't happy about it, but they let you keep it once they realize that they messed up by not letting you have both powers in the first place.
• The Legend of Zelda:
  • The Legend of Zelda: Four Swords and The Legend of Zelda: Four Swords Adventures only allow each player to have one item other than their sword at a time. If you pick up another one, the first item is dropped in its place.
  • The Legend of Zelda: Link's Awakening: In the Game Boy Colour remake, there is a Bonus Dungeon where Link can choose between either a red tunic that lets him deal more damage, or a blue one that lets him receive less damage.
• Metroid:
  • Though the Long Beam stacks with other beam powerups, Samus can only have either the Ice Beam or the Wave Beam at once in the original Metroid. It was technically possible to have both at once by cheating or mucking with the password system, most notably by inputting the NARPAS SWORD code, but this only resulted in Wave Beam shots with the color and properties of the Ice Beam.
  • Metroid II: Return of Samus: The same principle as that of the first game applies here, where there are Ice, Wave, Plasma, and Spazer Beams available to Samus, but she can still have only one at once.
  • Super Metroid downplays this with beam upgrades; the Spazer Beam and Plasma Beam cannot be equipped at the same time without glitching the game irrevocably, although the Ice and Wave Beams work together with either of the two and with each other. Later side-scrolling iterations in the Metroid series, including Zero Mission, just allow Samus to equip all beams at once.
  • The special exception is the second remake, Samus Returns. In that game, the Ice Beam is completely separate from all other beam powerups, save the Charge Beam. The Grapple Beam is separate from all of those as well, but it's always been separate. This gives Samus three settings for beam usage: a puzzle and anti-Metroid weapon (Ice Beam), an environmental traversal tool (Grapple Beam), and murder (all the other Beams at once).
• RemiLore: Lost Girl in the Lands of Lore: Switching the type of Starter Weapon, from Sword to Hammer for example, costs Dessert Points to activate the selected type, and simultaneously locks the previous one, needing to rebuy it if wanted again.

Arcade

• The old Arkanoid arcade game had this feature: when you acquired a new special ability by touching a power capsule, you lost whatever ability you currently had (if any). This had some annoying implications, as this includes any capsules that don't actually give you an ability (i.e. the slow and 1-up capsules, while not abilities, were mutually exclusive to anything you had at the time), as well as prevent you from getting ANY new capsules so long as the multiball capsule was in play.
  • Arkanoid II: Revenge of DoH showed why this was in effect. The game loosened up by dividing power-ups into two types — ones that are active on the Vaus (the paddle), and ones that are active on the ball. This trope was still in effect within each type (e.g. you couldn't combine Laser and Extend), but you could have one of each active — having Dispersion (the ball splits into 8) and Laser (can fire lasers from the Vaus) active at the same time turns many levels into a cakewalk.
• In Glider PRO, batteries and helium are mutually exclusive. Both are controlled by the same key, and helium wasn't in the initial release of the game.
• In The Tower of Druaga, the Green Ring, which protects you from one type of Invincible Minor Minion, is nullified by the Red Ring, which protects you from the other type of Invincible Minor Minion. Both are necessary pickups, because this game is just that cruel.

Fighting Games

• Dissidia Final Fantasy has this for Cecil's level 100 exclusive weapon. You can create either the Cimmerian Sword, which increases Dark Knight attacks, or the Lightbringer, which increases Paladin attacks. The catch is that following the exclusive weapon upgrade chain back to the beginning with the Dark Sword means that you can only have one or the other. No other character in the game has this restriction. That said, it is possible to obtain a second Dark Sword, if you know how to properly tweak the settings in custom battles against the CPU. In the sequel, he gets two new moves, each powering up one set of attacks. He cannot equip move attacks at once.
• The core concept of Spell Swap is that each character has one spell but can swap with the spell someone else is using if they manage to hit said opponent.

First Person Shooter

• Call of Duty games allows carrying two different weapons and no more^note The first game allows three, but one of them is always a pistol, and after the American campaign you don't always have one. Stuff like C4, Claymore mines, killstreak rewards, and, in very rare circumstances, specific types of weapons like RPGs or assault shields don't count against that limit.. You can exchange a weapon in your hand with one that's on the ground, but you can switch them back if you regret your decision (assuming it's still there). The decision of whether or not to pick up certain weapons at any given time can seriously affect the rest of the mission, though in most cases what you need for any given situation is what you started the mission with (such as a sniper rifle for intercepting enemies at long range) or something you can find a stash of right when it becomes necessary (like rocket-propelled grenades when heavy armor arrives).
• In Left 4 Dead and Left 4 Dead 2, you can only carry one weapon and item of each type — one primary weapon, one secondary weapon (or two, in one case), one grenade, one kit of some variety, and one extra healing item. Picking up a different one results in your old items being dropped on the ground in case another teammate needed it, or for you to take back once you've used the new one (such as dropping your medkit to give the team fire bullets, then taking the medkit back).
• Quake series:
  • The "Threewave CTF" Game Mod for Quake and Quake II have the Runes^note shaped after the game's own runes in I; the Disruptor Shield, Auto Doc, Time Accelerator and Power Amplifier in II. Players can hold one at a time, and they last until the players toss them, get fragged or commit suicide.
  • The Holdable items in Quake III: Arena^note Personal Teleporter and Medkit, Quake III: Team Arena and their Spiritual Successor OpenArena^note both of which include, in addition to the Medkit and the Teleporter, the Kamikaze and Invulnerability work this way. As their name implies, you can hold them and use it when you need it (provided you don't suicide or get fragged), but you can only hold one of these at a time. The same goes for the Team Arena/OpenArena's Runes^note Ammo Regen, Doubler, Guard, and Scout, which work the same as the Q2CTF Runes. In Quake Live, the Ammo Regen rune is replaced by the Armor Regen rune, which slowly regenerates armor rather than ammo.
• Rise of the Triad: Not only can you only have one active powerup at a time and grabbing a new one replaced the old one (apart from the bulletproof or asbestos vests, which are still mutually exclusive to each other), you can only have one missile weapon at a time. If you run across a bazooka while you are holding an Excalibat, for instance, you will leave the Excalibat on the floor as you grab the bazooka.
• Unreal series:
  • Unreal's Kevlar, Toxin and Asbestos Suits are all mutually exclusive: picking up one will automatically replace whichever of the other two you were previously wearing.
  • The Relics^note Defense, Redemption, Regeneration, Speed, Strength, and Vengeance added in the first Bonus Pack for Unreal Tournament work this way, requiring you to drop whatever one you have, thus losing its effects, to pick up another one and gain its effects.
  • Unreal Tournament III has the Deployables^note Spidermine Trap, X-Ray Field, Slow Field Generator (not to be confused with the "Slow Field" Timed Power-Up), Shield Generator, EMP Mine, Link Station and Shaped Charge. Picking up one of these prevents the players from picking up any other deployable (and even use weapons) until the deployable in question is used.

Platformer

• In Athena, the different types of weapons, which are frequently dropped by mooks, automatically replaced your current weapon if you touch them. Switching weapons is annoying, as the new weapon will be on the lowest level, where it takes multiple hits to kill enemies and in most cases can't even destroy blocks.
• Bug had the four kinds of Spit Wads. One was a regular shot, one was a double shot, one gave a shot that bounced along the floor, and the last was rapid fire. You could only have one at a time.
• Kirby can only have one power from a swallowed enemy at a time. Some games allow you to project that power in the form of a companion and swallow a different one.
  • Kirby 64: The Crystal Shards also allowed the pink blob to combine powers to create new ones, but only two at a time.
  • Kirby: Squeak Squad also lets you store up to 5 powerups in his belly at once, with a limited number of these being combinable (sword, fire, spark, ice & bomb, in certain combinations only).
  • And only having one animal friend at a time in Dream Land 2. The same goes for Dream Land 3, but in that case, you can have two players at once, and only one of them can ride at a time — if an unmounted player teams up, the other player automatically dismounts.
• The Mega Man series:
  • In Mega Man X3, you have the usual 4 capsules that give you new abilities, and each has an upgrade. They're normally mutually exclusive, forcing you to choose between a double air dash, auto-healing, increased defense, and a weapon that lets you fire Charge Shots continuously. There is, however, a secret way to get all of them at the same time, and get a nice golden color to your armor too!
  • In Mega Man X4, when playing as X, there are two possible arm upgrades. Either you get the Plasma Shot, a larger than normal Charge Shot that, when it hits enemies, leaves behind spheres that will do damage to enemies on contact, or the Stock Shot, the ability to build up to 4 regular Charge Shots in one charge, which can be released at will. You can switch whenever you want, by going back to where the capsules are (a little easier said than done, but...), but you can't have both. Interestingly enough, when the Fourth/Force Armor shows up in X5, it has the Plasma Shot, but with the Stock Shot's color scheme.
  • The later Mega Man Zero series' elemental chips can only be used one at a time, though it's not as much an issue since changing it out is as simple as going to the pause menu and swapping them. Because of this, EX skills from Zero 2 onwards zig-zag this: all of them can be active at once, but whereas saber-related skills are activated with specific button combos and/or under specific circumstances, buster-related skills simply change the effect of the Buster Shot's Charged Attack depending on which if any elemental chip you're currently using. Same for the unique Cyber-Elf in the fourth game: normally, while it has up to seven different levels for each ability, the player can only get one bonus for each ability (e.g. setting it to level 3 for Animal abilities, letting you shoot fire at enemies, doesn't give you level 1's increased running speed or level 2's slower wall-sliding). However, if the player fully raises the Elf and sets one of its abilities to max level, or plays in Ultimate mode, they promptly gain every preceding ability in that line.
  • Drill Man and Dive Man's stages in Rockman 4 Minus ∞ have Mega Man temporarily get the Sakugarne and Mirror Buster respectfully. You won't be able to use the other weapons while you use them. Meanwhile, in the final Dr. Cossack stage, the Screw Crusher, Ballade Cracker, and Spark Chaser replace the Mega Buster for the rest of the stage, but collecting them is optional.
• In Purple, you can't pick up another weapon without losing previous one on the way.
• Luigi cannot use the Athletic Peach and the Fire Flower at the same time in Something Else.
• The shields of Sonic 3 & Knuckles. This applies to pretty much every Sonic game that has multiple shield types.
• SpongeBob SquarePants: SuperSponge allows you to swap between equips and power-ups but you can only use one at a time and you can equip and unequip whenever to change to another weapon. You must drop the other items on the ground and leave them behind if you choose to continue on with your chosen weapon.
• In Sunsoft's Superman Licensed Game for the Sega Genesis, Superman's Sonic Punch and Hyper Spin powers share an activation button, and getting the icon for one power takes away the other. Heat Vision replaces both as well as Jump in the flying levels, but this is only a temporary side effect of the Unexpected Gameplay Change.
• Super Mario Bros. franchise:
  • Super Mario Bros. 3 added the mutually exclusive raccoon/tanuki/frog/hammer suits to the original game's Fire Flower. In Super Mario World, the flower and cape are mutually exclusive (though the Select Button box makes this less problematic). In New Super Mario Bros., the flower, blue shell, and Mini Mushroom are mutually exclusive, and getting the Mega Mushroom deletes whatever powerup you had. A strange exception is that if you get a Tanuki suit while using a P-Wing, the P-Wing effect will transfer from the Raccoon to the Tanuki.
  • In Super Mario 64, the Wing Cap and Metal Cap are mutually exclusive to each other (as far as anyone can tell; the two powerups almost never appear in the same area), but the Vanish Cap is not. Indeed, one particular star requires using the Vanish and Metal Caps together.
  • In Super Mario Sunshine, you always have FLUDD's Squirt nozzle, and can have only one of the secondary nozzles (Hover, Rocket or Turbo; the first one is the default) at once.
  • In Super Mario Galaxy 2, there's the various suits and Yoshi.
  • In Super Mario Maker, Mystery Mushroom characters cannot use any of the other power-ups in the game (though they can at least ride in the Kuribo Shoe). Thus, if you get a Super Mushroom or Fire Flower while playing as one of them, the character will revert to being Mario upon contact. Sorry, no Fire Marth for you.
  • Super Mario Maker 2: Each game style has, in addition to the Mushroom and the Fire Flower, at least two unique powerups (with the second batch added via an update). It is not possible to combine them, so you'll have to make sure you're using the right powerup for the current situation. The Super Mario Bros. game style has four specialized powerups: The Big Mushroom, Superball Flower, Master Sword and SMB2 Mushroom; the latter three powerups have Background Music Override attributes based on their games of origin, so by technical necessity the trope is justified for them.
  • Subverted in the Rom Hack Kaizo Mario 64, where all three caps are available in certain levels, and collecting all three simultaneously grants a silver shimmering flight capable Mario that can smash through enemies at will.
• The hats in the first Wario Land. Of course, there weren't many levels that required specific hats to be beaten, it really just came down to the play style of the player.
• The Special Items in Wizards & Warriors, which (with one exception) are all used with the Select button. Also, the Battle Ax replaces your Dagger of Throwing once you find it.

Pinball

• Mile High Pinball for the Nokia N-Gage allowed players to collect Bucks and purchase Power Ups, but only one could be active at any time.

Puzzle Games

• Jardinains!, a Breaking Out game:
  • Jardinains 2! has two sets of powerups that cannot be combined. If you have one in a set and get another one from the same set, you'll usually lose the one you had first. The first set are the ball powerups: Fire Ball, Ice Ball and Shock Ball. There's also the Impossiball, which combines Fire, Ice and Shock and trumps all of them. The second set consists of the weapons for your paddle: Fast Lasers, Fireball Cannon, Ice Cannon and Shock Lasers.
  • Averted with the Brickplow and Boomer ball powerups in Jardinains!. If you have one and catch the other, you'll get the effects of both.
• In the puzzle game Marble Blast Gold, the marble can only hold one powerup at a time. Partially averted as the powerup usually holds for a couple seconds after its use, so it's very easy to use several in rapid succession for extra effect (e.g. a super-speed followed by a super-jump, to get a very fast, long and high jump).

Racing Games

• In Diddy Kong Racing, running through a different-colored balloon will replace your current item, though hitting another balloon of the same type as yours will upgrade it instead.
• In the Gran Turismo series, on the rare occasions where you can even try, you cannot equip NA Tune, Turbine kits and later on Superchargers at the same time.
• In LEGO Racers, hitting a powerup brick when you already have one loaded swaps them. But if you have any white bricks (powerup upgrades), they stay with you.

Roguelike

• In The Binding of Isaac you can only carry one activated item, one pill or card, and one trinket at a time. As a result the d6, which lets you reroll items and can thus turn an activated item into a powerup item, is incredibly powerful. There's a powerup that lets you hold two trinkets, though. (Although to get to the final boss one of your trinkets has to be the Polaroid, which is near useless unless you're playing with only soul hearts.)
• In Crop Rotation, a crop can only have one mutation at a time. When merging two crops of the same kind but with different mutations, you have to choose which mutation to keep.
• FTL: Faster Than Light won't let you have a medbay and a clone bay on the same ship. The medbay allows you to heal your crew in combat (while they're in it); the clone bay imparts Resurrective Immortality and a per-jump Healing Factor, but the clone has their skills nerfed.
• Risk of Rain 2: Void items from the Survivors of the Void DLC are corrupted versions of normal items with similar but mechanically different effects. Void items corrupt all copies of their corresponding normal item when picked up, as well as all copies picked up later, which means that a player can never have both the normal and Void versions of an item at the same time.
• Spelunky features both a literal version of this trope — you can't equip the jetpack and the cape simultaneously; picking up one causes you to drop the other — and a more figurative version: the Spelunker can only carry one item in his hands. Deciding whether you want to carry a pick or a pistol is challenging enough, but it can be a real pain in the ass when you're trying to carry around a Damsel in Distress and a flare as well.

Action RPG

• Deus Ex does this with the Nano Machines, each only being usable in a specific slot. However, some slots came in multiples, allowing players to chose both the "mutually" exclusive augmentations if they wanted to. Only Legs, Eyes and Cranium were exclusive.
  • Deus Ex: Invisible War has all slots being exclusive.
• Mass Effect 2:
  • The game uses the inventory limit of 1 rule for your heavy weapons. However since your ship's fabrication unit never breaks, you never loses access to your list of heavy weapons, you just have to pre-select before each mission.
  • Some point into the game, you find a stockpile of Infinity Plus One Weapons. You only get to take one with you. (If your class can't equip the weapon you want, you get one normal weapon training instead. You don't get to pick another on a New Game Plus either).
  • Ammo powers upgrade a weapon to give it new tricks; you can only have one on at a time.

MMORPG

• City of Heroes used to have a similar occurrence, with Scrapper and Tanker defense powersets like Invulnerability, Stone Armor. All have powers that resist or defend against specific damage types (Smashing/Lethal, Fire/Cold, Psionic, etc.), and the first issue only allowed one shield to be toggled at one time...mercifully, this aspect was dropped fairly early.
  • It still exists in a more limited form. Stone Armor's Granite Armor is still exclusive with all the other armors in that set, and its Grounded ability de-toggles running and jumping powers. More generally, certain abilities that fit in the same power "slot" can't be active at once (e.g., you generally can't have two different Flight abilities activated at once, or two different Stealth abilities, or two different Jumping abilities, etc).
• Kingdom of Loathing, with the 2013 revamp of skill classes, added a set of self buffs that act like this, known as Facial Expressions. Every class has two, with the old skill Snarl of the Timberwolf becoming one of them.
• Several occurrences in World of Warcraft:
  • Mages can only have one armor spell active (Frost, Mage, or Molten).
  • Warlocks can only have one curse active on one target.
  • Shamans can only use one of their weapon enchants (Flametongue, Frostbrand, Windfury, Rockbiter, Earthliving) per weapon. They can also only place one totem of each element (Earth, Fire, Water, Air) at a time.
  • Rogues can only apply one Lethal poison at a time (either Deadly or Wound).
  • Paladins can only have one Seal and one Blessing at a time.
  • Hunters can only have one Aspect active at a time.
  • All classes can only have a potion and an elixir or a flask active.

RPG

• Avernum 6 has a set of mutually exclusive buffs for each priest (mutually exclusive protections) and mage (mutually exclusive attack buffs) classes of spells. Even if this weren't a totally unexpected shift in gameplay, players weren't happy about the artificial restriction on top of already high casting costs.
• In BoxxyQuest: The Gathering Storm, each character can equip one special accessory, and some of the accessories have effects that only work if they’re equipped by Catie, the party leader. So, for example, you can’t have both the Speedy Shoes (which allow you to sprint) and the Seeker’s Compass (which reveals hidden items) active at the same time.
• In Conqueror's Blade, each weapon has six special abilities and two ultimate abilities—but you can only equip three standard skills and one ultimate at a time. (Or you can forgo the ult and use four standard skills.)
• Fire Emblem Heroes: There are 4 Skill slots for each character labeled A, B, C, and S, with each slot only allowing you to equip one Skill for a total of 4. Every Skill in the game is also designated for a specific slot (e.g. Vantage and Quick Riposte are B Skills), so this means there are a number of Skills that are mutually exclusive with each other.
• Gauntlet: Dark Legacy. The items seemed to be divided into ten groups, but there were far more than ten items. So you could easily end up replacing a very good item with a very bad one.
• Knight Eternal: Each party member has to choose between two class emblems, which unlock different branches on their skill tree. Dylan has to choose between Assassin and Warlock, Astraea has to choose between Protector and Priestess, Goliath has to choose between Sentinel and Berserker, and Primrose has to choose between Dancer and Bard.
• In Lost Odyssey, either Kaim or Seth's best weapon can be chosen as your reward for completing a particular sidequest, which poses a problem when you are almost certainly using both of them in your party. Fortunately, Tolten's best weapon is better than either of them, and since you're just-as-certainly not using him, you can simply teach whoever didn't get their own best weapon the skill that allows them to equip Tolten's weapons and give them his instead.
• Pokémon:
  • Pokémon have only one item slot, and giving it an item when it's already holding something will replace the item it's holding. This means one can't give it a berry to heal damage and an item that boosts their strength.
  • Arceus and Silvally can change types with specific items, but this comes at the cost of them being unable to use other hold items. This also applies to certain Pokémon with alternate forms (i.e. Giratina, Kyogre and Groudon) or Mega Evolutions, the one exception being Rayquaza (and even then, giving it a Z-Crystal stops it from being able to Mega Evolve, so it can't do that and use a Z-Move).
• Shin Megami Tensei:
  • In Shin Megami Tensei: Strange Journey, there's the EX Mission "The Mecha Dragon's Secret," in which a crewmember tasks you with negotiating with Fafnir (a robotic dragon in Sector H) for a piece of itself so he can research its technology. If successful, Fafnir will gladly give up a fragment of its own body —either a Dragon Screw, a Dragon Scale, or a Dragon Circuit. The crewmember will then fashion that one item into a sword, a vest, or a ring, and (unless you farm the components for the Dragon Vest elsewhere) you can't have any other item unless you go through the game another couple of times and negotiate the other pieces from Fafnir again.
  • In Soul Hackers 2, the final tier of each weapon upgrade is considered a Master Upgrade. Installing a second Master Upgrade onto a COMP will revert the previous one to the previous tier.
• In various Super Robot Wars games, there are Mutually Exclusive Secret Characters and robots; for example, in Z, you can unlock either the Xabungle Unit-2 or Ray and Charles depending on your route split choices, and there are many secrets exclusive to one of the protagonists.
  • Shin Super Robot Wars: Let the Taikuu Maryuu be attacked by the Shiki Death Squad in Scenario 25 of the Earth route to get Fortified Layzner in scenario 33 of the Earth route. Otherwise, get the Layzner Mk. II. Also, the upgrades to the V2 you'll get later depend on whether any shuttles get shot down in Scenario 21 of the Space Route.

Shoot Em Up

• Most Shoot Em Ups by Compile feature a variety of weapons which can only be held one at a time:
  • Blazing Lazers has four kinds of mutually exclusive options on top of four types of mutually exclusive weapons.
  • Gun Nac features 6 upgrade paths for weapons, but only one can be upgraded at a time. Getting a different powerup doesn't upgrade, but resets your weapon type to the pickup's, at level 1. However, if you don't die you can keep swapping weapons and they'll retain their previous strength. This does not apply to bombs.
  • Aversions: Guardic, The Guardian Legend and Spriggan Mark II allow freedom of weapon selection.
• Fire Shark has three powerups, the blue which provided a weak but fast spread shot, green which provided a narrow but extremely strong laser, and red which give your plane the strong flamethrower which swept the entire area.
• Double and Laser are exclusive in Gradius, as are Ripple and Laser in relevant sequels (In other games, Ripple is considered a type of Laser).
• In the Parodius games, Bell Power cancels your ship's shield equivalent.
• Raiden has this for both the player's main weapon (guns) and sub-weapon (missiles).
  • For the guns, you have either the Spread bullets, which can fill the screen at max level, the laser, which is tight but extremely powerful, and from II onwards, a purple laser that can twist and lock onto targets but is less powerful than the basic laser. III replaces the homing laser with a "Photon Laser", and IV dives a little further into this trope by letting you decide what weapon to pick up from purple powerups (photon or homing).
  • For the missiles, you choose between hard-hitting unguided rockets and agile homing missiles.
  • This allows a player to achieve a personal balance between focused firepower and maximum screen clearing. Given the fact that the game keeps throwing both swarm enemies and tough enemies at you all the way to the end, there is no clear winning combination.
• The spaceship in R-Type can only hold one of the three lasers at a time.
• Tyrian's Arcade Mode and Super Arcade Mode have this. In order to power up your weapon, you have to collect the same color powerup that your ship is using. Grab the wrong color (easy to do at times) and you're stuck with a new, low-level weapon.
• NES game Twin Eagle had four different weapon power-ups—conveniently color coded—that could be powered up three times. Getting the same power-up would increase it, but getting a different power-up would change weapon type while keeping the equivalent level.
• Warblade, a very deep and complex shmup, allows you to keep one weapon at a time. If your ship either explodes or touches a skull, your weapon downgrades and your stats lower a bit. This leads to Unstable Equilibrium situations. It truly sucks when you're perfectly fine with your War 1 Plasma weapon and you pick up a double shot powerup by mistake. Weapons more powerful than Quadruple Shot must be bought from shops, where they're pretty darn expensive, too. The most expensive one costs 3000 credits, but that's still nothing compared to the cost of re-buying all your powerups if your ship explodes if you're well established.. Let me see... 30000 super autofire + 15000 alien lock +3000 weapon + 1625 stat bonuses. So about 50000 credits.
• ZeroRanger goes a step further with this trope. At the end of each of the first three stages, you are presented with two different choices of a new weapon, and when you pick up one of those weapons, the other becomes unavailable until the second loop. For example, at the end of stage 1, if you obtain the side-shot weapon, you cannot get the back-shot, or vice versa. The only way around this is in a 2-player game, in which case the other player can take the weapon you didn't pick.

Sports Games

• All Backyard Sports games except for baseball and football have this trait for powerups.

Strategy

• In Attack of the Mutant Penguins, you can only hold one kind of special item at a time.
• Every unit in Battle Realms can only have one Battle Gear at any time. While Zen Masters, Monks and Ninja only have one anyway, most units usually have a choice between two or more, depending on the player's preference. For example, the Dragon Clan's Samurai can either get Yang Blade from the Shrine (which boosts Yang generation and damage the more Yang the player has) or Dragon Skin from the Fireworks Factory (which boosts the Samurai's resistance to projectiles).
• Bloons Tower Defense 6 has three different upgrade paths for each tower. Each path has up to five levels, but taking two paths locks you out of the third path and you can only upgrade one path past level 2. Some towers have a Paragon versions that requires fusing three maxed out towers of different paths into one.
• Civilization V: Any given city can have a nuclear power plant or a solar plant, but not both. These have the exact same effect (increasing city production), but the nuclear power plant requires Uranium and the solar plant doesn't, providing an unusually subtle Green Aesop: ecology helps you save resources that are limited^note And devote more of them to bombing other people. Well, we said green aesop, not pacifist aesop..
• Civilization VI has a handful:
  • The base game has the Encampment, where the player can either choose a Barracks^note increased experience for melee, ranged, and anti-cavalry units or Stables^note increased experience for cavalry units, and the Theater Square, where the player can choose between two buildings that hold two different types of Great Works: the Art Museum^note Great Works of Art or the Archeology Museum^note Artifacts. The second expansion, Gathering Storm, adds a fourth tier of buildings to the Industrial Zone: Power Plants, each of which use a different resource^note Coal, Oil, or Uranium to power nearby cities. Thankfully, you can change which Power Plant you have if one ends up straining your resources, but it takes up precious Production in a city to do so. The base game also has the Holy Site, where you can choose up to nine different final tier buildings, but the city's majority relgion is the one that chooses the building, and the religion must have chosen the building. The Neighborhood district added a MEP in the first expansion between the Food Market^note Food and the Shopping Mall^note Tourism, Gold, and Amenities.
  • The first expansion, Rise & Fall, adds a new district with a double layer of Mutually Exclusive Power Ups with the Government Plaza. The first is once you reach a new tier of governments and start using one of them, you can build a new tier set of buildings in a constructed Government Plaza, each with their own unique and powerful bonuses. In addition, you get a legacy Policy Card based on whichever government you had when the finishing construction the building.
  • There's also MEP on Districts with the two Entertainment ones, the Entertainment Complex and the Water Park. Both pretty much do the same thing, but the Entertainment Complex can only be built on land and has some Wonders connected to it while the Water Park must be built on the Coast. Also, their second tier buildings give Science, but from different sources.
• Dawn of War 2 lets you pick one of between two and four different pieces of Wargear for each of your commander's three slots. You can change your mind later, but you'll have to pay for the new equipment, and it takes time to switch back.
• In Defense of the Ancients some items have "Orb Effects" that increase the power of an item in some way. Heroes are only allowed to have one Orb effect at a time. This is a limitation of the Warcraft III engine, since effects that modify the appearance of a ranged attack's projectile don't stack. DotA decided to use this trait as a balancing mechanic for items. And while multiple effects from multiple buffs can stack, two different ones won't stack if they're both based on the same buff.
• In Fire Emblem: Thracia 776, the Wrath and Vantage skills cannot be combined on one character (attempts to do so will have Vantage take precedence). This is due to the fact that Vantage causes a character to always attack first, while Wrath can only activate if the character is attacking after the enemy.
• Starcraft II:
  • Wings of Liberty: Protoss and Zerg-inspired upgrades aren't mutually exclusive, instead each techtree has two mutually-exclusive upgrades (such as increasing attack speed with every attack upgrade or increasing HP with every armor upgrade) or unit choices (such as a ground-attack robot panther or a massive dropship). Individual unit upgrades aren't exclusive, but they all cost credits (and you can't get enough credits to buy everything). Unlike later games, you're stuck with the upgrades you chose during the campaign, including if you redo individual missions.
  • In Starcraft II Heart Of The Swarm, several units get a mutation and an evolution but can only select one of each. While you can change which mutation each gets between missions, evolutions are permanent. For example, once you choose whether your Hydralisks can evolve into the anti-armor Impalers or the anti-infantry Lurkers, you're stuck with that choice (at least for that playthrough: playing a single mission at a time lets you choose the upgraded form you want). But you can change between greater range, more health, or increasing their attack speed any time between missions.
• In Valkyria Chronicles, a fat enough wallet can purchase permanent stat upgrades to the Edelweiss, as well as additional mix-and-match parts. However, the final tier of upgrades gives you a choice: you can beef up its armor, its body or its targeting systems, but never more than one at once. And switching among them requires you to fork over the hefty R&D fee every single time.

Non-Video Game

• Doubutsu Sentai Zyuohger: The Red Ranger has three different modes that he can switch between. His Zyuoh Eagle form gives him the ability to fly, Zyuoh Gorilla gives him super strength, and Zyuoh Whale gives him water powers and a powerful Hand Cannon. At least until the final episode reveals that he actually has an additional form that combines all three powers.
• Dragon Ball: This was originally the case with the Kaio-Ken and Super Saiyan powerups: It was impossible to use both at the same time as Super Saiyan required an angry heart, and putting Kaio-Ken on top of that was too dangerous and would almost certainly lead to the user's death (although Goku did do it for a split second in a filler episode in the anime). Later subverted with Dragon Ball Super, where Goku was able to use Kaio-Ken along with Super Saiyan Blue, because the latter transformation was more calm in nature and could handle it.
• Grrl Power: Halo gets her powers from the seven mysterious orbs that float around her, but she has to be holding an orb in her hand to use its powers, and as such can only use two orbs at once.
• Kamen Rider Fourze has a set of forty pieces of equipment that he can equip on his arms and legs — ten on each limb, and he can't just take one and swap it to another limb. In addition, some of his right-arm weapons change his form, so those forms are locked out of using any other right-arm equipment (and the Mid-Season Upgrade uses up his left-arm slot as well). His Super Mode has the explicit advantage of breaking this limitation, letting him activate multiple pieces of same-limb equipment and combine them.
• Pokémon Journeys: The Series: The rules of World Coronation Series explicitly restrict trainers to using one of Mega Evolution, Z-Move or Dynamax per match. A trainer can send out a Pokémon capable of each, but once they use a power-up the other two are off limits to give a fighting chance to opponents with access to only one (or none at all). However, Leon defies this in the Final Battle, requesting that Ash be allowed to cut loose on him with everything he's got. The officials accede to his request.

Real Life

• DSL internet service is faster than dial-up and relatively cheap because it's still piggybacking on your phone line. VoIP call service (offered by companies like Vonage, as opposed to applications like Skype) saves money by piggybacking on your internet service. As Tailsteak explains, this means you can't have both — signing up for one when you already have the other will cause you to be disconnected entirely.
• When it comes to pistol rounds, armor-piercing and hollow-point bullets both offer an advantage over standard "ball" ammo, but "armor-piercing, hollow point bullets" are an oxymoron; it's impossible for a single round to do the work of both. Armor-piercing bullets penetrate very well, but pass through a target without doing much extra damage, while hollow-points open up and cause bigger wounds, but are a whole lot more likely to be stopped by even a lightweight bulletproof vest. This dichotomy is less pronounced in more powerful handgun and rifle cartridges, which are usually throwing a heavier chunk of lead at a high enough speed to beat many types of body armor anyway.
• No natural material has all of the desirable traits (strength, flexibility, malleability, etc.) for everything we'd want to make without at least one or two downsides (brittleness, fragility, weight, etc.)—this is why high fantasy and science fiction alike is full of unobtainium. Not that this has stopped humanity from looking for new resources or, if it really is not possible for it to exist, synthesize it.
• Often said by those in the repair, design, or customer service industries — "We offer three kinds of services. Good, cheap, and fast. Pick any two you want."

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