So You Want To / Make a Metroidvania

So... let's get straight to the point—if you're reading this, you probably already know what a Metroidvania is (or at least know one when you see one): An Action-Adventure game based around exploring an environment which contains the means to access new areas. From a narrative point of view, this means that you should remember to:

1. Keep the story integrated: The plot should tend towards "Natural" or "Deliberate" integration on the Sliding Scale of Gameplay and Story Integration. Much of the appeal of the genre comes from exploring a consistent world, so jerking the player away from it is a definite no-no. See the Necessary Tropes section for ideas on how to integrate common gameplay elements into the story.
2. Give the Player a reason to explore: This can be as simple as "MacGuffin and Plot Coupons somewhere. Find." It can also be a more complicated story with a shifting goal^e.g.You begin exploring the Startzone Ruins, only to be ambushed by Plotpush Pete. After searching for clues, you find he's headed to the Temple of Uh-Oh, only to.... Just as long as the player has something to look for and more than one place to search.
3. Follow the Player Character: The PC is the player's avatar as they explore the environment. Try to keep the narrative firmly from their perspective and information that only one or the other know to a minimum. If you want to cut elsewhere then do so when the PC is doing something uninteresting, like traveling from area to area or explaining something to an NPC.
4. It's easier to write a story than avoid one: The gameplay in a Metroidvania creates a sort of narrative of its own; the Player Character grows, even if their personality isn't developed, and the players, themselves, will (hopefully) go on a journey from a single square on the map to knowing every nook and cranny. Take advantage of it, but remember...
5. ...never let the story trump gameplay: Ideally the two should be complementing one another, but (in this genre) the game is the means by which the story is being told; if you hamper it, they'll both suffer.
6. Plan everything: As with any game, make sure you've written the story (or at least a synopsis) and sketched out the levels (including any Event Flags and puzzles) before anything else. Not only will it make it easier to put together, but it'll give you (and anyone else working on the game) an easy-to-use source.

With all that in mind, consider how you're going to tell the story:

1. Dialogue: A quick chat with an NPC is among the simplest ways to explain something to the player (although a sign or recorded message works too, if they're the shy sort). Just beware of dumping too much information on the player and remember that some players tend to skip dialogue. If the conversation is caused by an Event Flag, make sure they do something useful (being forced into idle chatter will probably just irritate the player, rather than help immerse them).
2. Cut Scene: As mentioned above, it's best to avoid taking control from the player for too long^note This can be mitigated by putting them in between-level transitions and other places where the player might expect to lose control, but that doesn't mean it should be avoided entirely; cutscenes are a great way to introduce new equipment, areas, monsters, and boss fights. Just remember that if you place a 10-minute-long cinematic just after That One Boss, the player's very likely to be more concerned with saving the game than with the story.
3. The Environment: Even if the player character never interacts with another intelligent being or speaks a single word, abandoned camps, ruined civilizations, or even some non-hostile fauna can all (to use a clichéd expression) tell their own story. In addition, changes to older areas (in addition to reassuring the player they're getting somewhere) can create a sense of a moving narrative as well as add a bit of variety to the Back Tracking ("Who left this rabid wilderbeast here!?") or serve as a not-too-specific clue where to go next ("So where did that come from...").
4. Clues: Somewhere inbetween dialogue and letting the environment speak for itself, there are the things the player can take a closer look at or ignore. These can be journals and other collectable documents (See Story Breadcrumbs in "Choices, Choices" for more details), information about the world (bestiaries, character profiles, etc.) or just objects the player can get a bit more information about with the tap of an action button.

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Necessary Tropes

Quite a few of the genre's mainstays fit any sort of story:

• Ability Required to Proceed: The abilities can be dressed up any way you like; Powers as Programs, Mega Manning, Equipment-Based Progression, How-to Guides.
• Boss Fight: A good boss fight, aside from representing a challenge, reassures players they're headed in the right direction (why else would there be a boss in the way?). It can also be used to "train" them in using a new ability, either by having them use a newly acquired tool to defeat it (e.g., if the hammer can be used to smash rocks and stun the boss, give it armour like those rocks!) or by making it clear that the tool would have made the fight easier (e.g., by having the player smash through the boss's remains with the hammer it was guarding).
• Door to Before: One of the more common complaints about backtracking comes from having to constantly retread old ground; forcing the player to "travel" gets old fast. If the player's already been through an area and there's nothing else there (bonuses aside), give them a shortcut. This is usually as simple as having a shorter route which requires whatever skill the player picks up at the end of the area in question.^example Super Metroid provides an example here. The upper-right of Maridia has a one-way passage into the top portion of Brinstar, right near your ship. It appears to serve no purpose, since it requires a Super Missile, which you will certainly have by the time you ever see it from the Maridia side. It's purpose is to allow you to leave the upper part of Marida after killing Draygon easily. Without it, the only ways out are either at the bottom of Red Brinstar or on the other side of the Ghost Ship.
• Foreshadowing: Always make sure that there are a few easily noticed obstacles in the early areas. This will give the player a reason to return when they've picked up whatever equipment they need to get past it (and hopefully notice some more subtle extras).
• Disconnected Side Area: These often have some goodies at the end, but they can also be part of a subplot/Side Quest aside from the main story.
• 100% Completion: Most Metroidvanias reward the player according to how much progression is made over the course of the campaign. The percentage may be sorted by collection of items, unveiling of the map rooms, simply by advancing through the story, or all of them at the same time. The rewards may be Multiple Endings and/or out-of-game Unlockable Content (Concept Art Gallery, characters or stages for multiplayer, Replay Mode, Sound Test, etc.). The options are plentiful.
• Justified Tutorial: In a sense a Metroidvania is a justified tutorial stretched over an entire game. Each new piece of gear the player picks up should introduce a new mechanic, and the area or boss fight around it should be designed to show the player how to use it.
• Level-Map Display: At the very least, it should show the player the rooms they've been in and where they currently are. Marking Save Points and other notable types of room is considered polite. Marking rooms with undiscovered secrets is optional, but really helps avert Last Lousy Point.
• Sequence Breaking: Even if you don't leave in ways to break the normal sequence of events, assume the player will find some. Think ahead and come up with ways to accommodate every possibility (as a rule of thumb, Breaking the Fourth Wall's perfectly acceptable if the player had to do so to get there). Include "backup" obstacles behind later ones (e.g., if the player isn't meant to have the red keycard until the endgame, make sure there're a few doors locked with interim key cards, or come up with a plausible Broken Bridge), but leave some sort of bonus before them so the player doesn't feel cheated.
• Sliding Scale of Linearity vs. Openness: Aim for a 3 or 4; there should be a fixed sequence of events to follow, but the player should be free to explore and find it on their own.
• Video Game Tools: Remember that each of these should introduce a new mechanic (or at least tweak an old one enough to make a difference). Give each one at least one obstacle it can overcome.

Choices, Choices

• Broken Bridge: These are best used sparingly (the player's supposed to be getting the ability to get past obstacles, not have them removed for them), but they can still work (especially when they mark major turning points in the plot). They're also good way to implement the Door to Before.
• Dungeon Shop: There's nothing wrong with including a town, but since most metroidvania are mostly dungeon anyway, this is a good way to allow the player to avoid having to constantly travel back to it. It's also a good way to let the player stock up just before you make life difficult for them.
• Dungeon Maintenance: Making this a plot point can be used to explain a lot of tropes (see Potential Subversions below).
• Multiple Endings: Altering the story based on the player's choices is a good way to add replay value or simply act as a gauge of how well the player did (e.g., if they unlock everything they get the Golden Ending).
• Pacifist Run: These always add a bit of replay value (heck, who said you even need enemies?).
• Railroading: This is a double edged sword; it's recommended to use this to give the player a sense of direction and keep them from getting lost or overwhelmed from having too many choices at once, but in moderation—giving a player too few choices on where to go or what to do and constantly holding the players hand is detrimental to a Metroidvania.
• Random Drops/RPG Elements: XP and new gear can make good "filler" in between finding new Tools. Elemental Crafting and Item Crafting are optional.
• Reviving Enemy: These can be a good way to make a formerly safe area more dangerous or just provide an obstacle in the form of a Beef Gate.
• Roaming Enemy: These match up perfectly with large environments. Any of the variations mentioned on the page are a good way to give the player a sense of being hunted or chased, or just make the world feel more "alive".
• Save Point: In the distant future of the 21st Century, computers and consoles have enough memory that any game can have a "save anywhere" feature. That said, it's hard to imagine a metroidvania without them (where's the fun in deciding whether or not to press on if there isn't any risk?). Auto-Save features can co-exist, but avoid letting the player Save Scum.
• Story Breadcrumbs: These are perfect for fleshing out the story (or just the Back Story of an area) without the need to distract the player (they can just read or listen to them when they feel like it).
• Utility Weapon: Giving a tool an offensive use is a good way to make the player feel more powerful (you can even make killing a certain enemy one of the tool's uses!), but isn't necessary.
• Warp Whistle: This can make travelling a lot less frustrating, but might discourage players from exploring too much. If there's a Hub Level of some kind, this is closer to mandatory - you need to be able to get out and back with relative ease.

Pitfalls

• Ability Required to Proceed: Smashing the same obstacle again and again isn't a puzzle on its own. Do your best to use your obstacles in interesting ways (Lighting torches opens doors? Make some of them traps which explode when lit or introduce a means of putting torches out and have the player work out the pattern!). Remember that while most games in the genre assume you'll need to "pick up" the abilities (i.e. you won't have all of them available from the start), this isn't mandatory. Games like Toki Tori have demonstrated that it's perfectly possible to preserve the essence of this trope while having every ability available from the start (see here for a quick explanation). Super Metroid also famously had "hidden" abilities that the player could use from the start (in the case of the wall jump), but were only revealed by hints late in the game, rather than shown to the player or mentioned in the manual.
• Level Grinding/Money Grinding: Or, even worse, Forced Level-Grinding. Making the player do this goes pretty strongly against the idea of a game based around exploration (they'll want to be exploring new areas, not killing the same room full of mooks over and over again!). If the player can level up, make sure to balance things so that they will never need to grind to be able to progress, with the possible exception of optional end-game content.
• Lock and Key Puzzle: There's nothing inherently wrong with including a few, but it's very important that this doesn't become the case with the abilities the player requires to proceed:
  • Having a few obvious obstacles along the critical path for the player to remember and return to when they have the relevant ability is nice, but what might as well be a smashable block or switch which requires the relevant item to interact with gets old quickly^note The original Metroid games did indeed use beams as glorified door keys to block off certain areas and shortcuts, but also offset this by making them Utility Weapons; the Metroid Prime games improved things by having the player use the scan visor to identify certain materials that needed a given weapon to destroy, turning it into a logic puzzle of sorts.
  • Consider all the things a given ability could be used for; you can even let the player work out a few of the more exotic uses to make optional content that little bit more rewarding^note Going back to Metroid; the shinespark technique was a hidden use of the speed boost ability which the player would have to discover accidentally by crouching after charging it up. The most interesting abilities allow the player to deal with obstacles, not bypass them without thinking (e.g. if you give the player the ability to double jump, let them access new areas by jumping over tall crates, but also give them jumping puzzles that take into account their longer jumps).
  • Combining abilities is also a good idea (e.g. have the player return to an area with the ability to double jump and get some goodies on higher platforms, but at the same time, notice a few that are hidden behind platforms that they can't interact with yet; when they get the ability needed to use those platforms, they're sure to remember the area).
  • A final thing to consider is that new abilities could make older puzzles easier (e.g. single-jump based puzzles can be spaced so that the player can just double jump over them without thinking; puzzles in areas where players take damage become easier when the player has the ability which protects them). This can be used to reward players who accept more of a challenge (by letting them get bonuses earlier), or simply make backtracking easier without outright letting them use a shortcut (e.g. the aforementioned single-jump platform puzzle goes from a 10 minute test of precision jumping skills to just another corridor the player can hop through in moments).
• No Sidepaths, No Exploration, No Freedom: It goes without saying that this is a bad idea. Make sure that each area has plenty of extra areas for the player to discover. As a rule of thumb, include at least one other path (with a reward at the end) for each one which will advance the story (and ideally more, if there's time).
• Now, Where Was I Going Again?: Design the "official" path to completing the game with the assumption that the player might take a break for a month (or longer) before coming back to it at any time (or just skip the cutscene where they were told where to go). If there's anything that relies on them being specifically told where to go (or what they need to do), make sure there's somewhere for them to hear it again. Include notes and markers on the map (or let the player add their own, if the engine supports it!).
• Permanently Missable Content: Always give the player the chance to go back and collect things they missed (or at the very least make something that's about to be lost so obvious it's the player's fault if they don't pick it up, and relatively inconsequential).
• Plot Coupon: It's generally not a good idea in a Metroidvania to segregate abilities and keys from each other—each ability should not only serve as the key to accessing a new area, but also enhance or change the nature of the gameplay itself.
• Quicksand Box: While Metroidvania aren't as prone to this as Wide-Open Sandbox games, you should take care not to overwhelm the player. Dot the path to the end of the game with set pieces and triggers, so they know they're on it, and always include rewards at the end of sidepaths (so they don't feel like their efforts were wasted and they know that they've finished following them).
• Rare Random Drop: As with levels, it's always best to avoid forcing the player to grind for something. If you want to make something hard to find, tuck it into a distant corner of the map or put it in a secret passage.
• Wake-Up Call Boss: A Difficulty Spike isn't inherently bad as long as the game isn't rendered unbeatable because of it, but do try to make the difficulty curve grow naturally, especially if you intend to start the game in the middle of a battle (it has happened). Bosses that are very difficult because they're a Beef Gate to block the way to places that are meant to be cleared later in the game are okay, though.
• You Have Researched Breathing: It's also not a good idea to make an ability that should already be a natural move for the character into something you have to learn. It's an even worse idea to only make it useful in ridiculously specific circumstances, such as only being used to unlock a new area and for little else.

Potential Subversions

• Amnesiac Hero: This is pretty overdone (since it's a handy way to have the player learn everything), so if you want to use it, try and do something clever with it. Consider giving everyone amnesia (or make the PC the only one without), or have them remember who they are but lose their skills; or make the fact that they have amnesia at all a plot twist (Fake Memories optional). You could even give the hero Anterograde amnesia (when they can't form new memories) and have them constantly lose memories of what they've been doing.
• Backtracking: The player should end up revisiting old areas at least once, but don't expect them to do it on their own. Drop hints or offer incentives (e.g. "Hmm, wasn't there a statue like this one back in..."). Or better yet, why not surprise the player (pleasantly or otherwise) with something unexpected on the way back, like a Boss (figuratively or literally) or an unexpected shortcut (beware that the latter might annoy them if its one-way and they planned to keep searching a bit).
• Benevolent Architecture/Malevolent Architecture: Conspicuously helpful or dangerous parts of the environment can be jarring, but you'll get away with them. Still, it's perfectly possible to come up with an In-Universe reason for them (Traps? Actually being designed for someone with the tools/abilities your player picks up?). The line between the two can also be blurred (maybe the player could end up somewhere designed to trap people with certain skills? Or perhaps a treasure could be hidden with a fake trap^note Just give the player a hint so they don't try running into every trap "just in case".).
• Heart Container: You don't strictly need these, but they make great rewards. Consider using them in interesting ways (like having the player pick up ammo and expansions for weapons they've yet to pick up, or having them weaken the player as some sort of challenge or tradeoff). In more grounded settings they can be things like armour or just larger containers for health packs and the like. In more fantastic settings, they could be literal containers of life force or magical power.
• Mutually Exclusive Power-Ups: Be wary of making the player trek back to an older location just to switch powerups out, but this can still make for an interesting mechanic (or replay value, if the player has to stick with their choice for the rest of the game).
• Point of No Return: In a game based around 100% Completion, it's best to allow the player to backtrack at any point, short of the Final Boss (and even then...). Alternatively, why not make the "final" area not-so-final (it worked for Castlevania)?
• Respawning Enemies: Most metroidvanias have 'em, but that doesn't mean you can't do something new. Consider keeping a count of how often the player kills the Mascot Mook. You could also have enemies replaced with Elite Mooks or otherwise powered up over the course of the game (or in response to the aforementioned kill counter). Think about deconstructing the idea of killing all the flora and fauna you encounter; maybe you could just avoid it? Befriend it? Perhaps some enemies might even go extinct if you kill them often enough....
• Suspicious Videogame Generosity: This trope exists partly because it's logical to give the players extra resources before challenging them. Why not allow them to bypass the resources for extra rewards after the fight. Or just give them stuff for free just to make them jumpy. Inverting it, by having the boss consume potential resources before the player got there, is another possibility.

Terrain Recycling

Metroidvania games, as a matter of course, involve a degree of forced Back Tracking. This can make a game feel tedious or cheap (for reusing terrain rather than making new terrain). But there are ways to make it feel substantially less so. These effectively make old terrain feel like new terrain.

• Enemy Evolution: One problem that forced backtracking causes is that many enemy challenges in an area will no longer be challenging the second time the player enters the area. If the main sequence of play sends a player through old terrain, it may be important for the player to still be challenged through combat. So you should find a way to spawn different enemies in that area.^exampleMetroid: Fusion did this excellently in your second trip to Sector 2: TRO. In the first trip, you run across some worm enemies, who's only real power is absorbing a lot of damage before dying. Once you beat a boss, they turn into cocoons (which also block your access to certain areas the game doesn't want you to access yet). Later on, the cocoons hatch, and turn into very dangerous enemies that deal 50 damage per-hit (without the Gravity Suit).
  
  This must be used with discretion and judgment, particularly towards the end of the game. When the player starts getting up to late-game exploration, you want them to be able to navigate most old terrain quickly and effectively. And this means letting the player bypass enemies much more easily than before.^exampleThis is the purpose of the screw attack in most 2D Metroid games. It makes killing (most) enemies effortless, and allow you to do so while on the move.
• New Terrain: Use some fragments of new terrain before the player gets to the old terrain. Not only does this help sell the world as being cohesive, it helps the player feel like they're still on the right path, even though they just came back to a place they already were.
• Terrain Evolution: Make changes to the terrain. This should be justified by the story in some way; perhaps the actions of the antagonist are causing this. Note that you should make sure that, when modifying terrain in a way that changes what you can and cannot reach (for example, a wall collapses and covers an exit), the map should be updated accordingly.^exampleMetroid: Fusion did not do this, which made the end-game scavenger hunt somewhat annoying. Particularly in Sector 2, where a passage looked passable on the map but was not, forcing a long detour.
• Added Exploration: Give them something new to do the next time they come by. The last time they were here, they should have seen something that they couldn't reach. When you force them to come back, you should make sure that they have any abilities needed to reach those locations. Even if the rewards aren't very big, they do help the old terrain feel new.^exampleAfter getting the Speed Booster and Ice Beam in Super Metroid, you can leave Red Brinstar by heading back into Blue Brinstar. If you do, you will be able to use your newly-found gear to get all kinds of goodies.

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Writers' Lounge

Suggested Themes and Aesops

• Apathy Killed the Cat: This gels nicely with the idea of exploration and adventure.
• Curiosity Killed the Cast: Despite the above, Deconstructions of the player's motives are certainly in vogue, as of the 2010s. Why not call the player out and tell them they could have walked away (i.e. stopped playing the game...you're meant to be encouraging them to play)?

Potential Motifs

It's helpful to give important characters motifs. In the case of the PC and friendly NPCs it allows you to mark safe or helpful objects. For enemies (be they normal monsters or the Big Bad themselves), it allows you to tease the player with their presence without outright saying they're there. The latter is especially helpful at giving a Roaming Enemy a Vagueness Is Coming style warning to the player.

A motif could be anything from a sigil, which shows up on things associated with them, to a sound, to simply having things Colour-Coded for Your Convenience.

Suggested Plots

• Bold Explorer: Have the protagonist explore for the sake of exploring. This might seem like a shallow plot, at first, but it accurately mirrors the player's reason for playing the game (and they can always stumble across plenty of secondary plots).
• Distress Call: These are a good way to get the main character out to an isolated location with whatever abilities and equipment you want to start them off with (you could always have them drop their suitcase if they're sensible enough to bring anything extra).
• Late to the Tragedy is a good way to set up a hostile location and leave the player to piece things together as they explore it. Reasons for the tragedy can include:
  • Big Damn Heroes: Why not subvert it, and have the player show up Just in Time to fix things?
  • Dug Too Deep: And now the player can follow in their footsteps!
  • No Party Like a Donner Party: A bunch of people ran out of supplies and turned on each other. Expect any survivors to have gone off the deep end.
  • Slept Through the Apocalypse: The protagonist wakes up and everything's in ruins.
  • Unexpectedly Abandoned: The PC shows up somewhere and finds it deserted. Time to start looking for people (and answers)!
• An MMORPG style plot, with multiple players (or just NPCs) wandering around the same dungeons after the Infinity +1 Sword or the plot.
• Stern Chase: Have the player character tracking someone down. Or rather than have your PC search, have them being chased and looking for a place to hide (time limit optional).

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Departments

Set Designer / Location Scout

It's important to make sure that your game's world has more than one type of environment to explore:

• Abandoned Mine: These always have potential; tools scattered everywhere, plenty of natural barriers and maybe even Mole Men or an Advanced Ancient Acropolis far enough down.
• Ancient Tomb: Aside from the obvious traps, this presents the opportunity to give the player Lost Technology to handwave platforming elements in more grounded settings.
• City of Adventure: The "normal" city can serve as a Hub Level (or be a Ghost City), with an Absurdly Spacious Sewer, The City Narrows, a Haunted House, Sinister Subway or a mysterious Undercity being potential locations for levels.
• Haunted Castle: You might have some trouble getting different looking tilesets (although gardens and hidden Mad Scientist Laboratory's are fairly easy to include), but otherwise a large castle is a perfectly respectable setting, especially if you want a horror theme.
• Mad Scientist Laboratory/Abandoned Laboratory: As you may have guessed from the other entries, these can fit in anywhere, as long as the setting itself allows it; Mysterious cabin? Alchemy lab in the cellar! Mansion? Check behind the clock! Government building? Caves? Your eccentric aunt's house? Treehouses? Phone booths? That irritable IT's guy's office? Bookcases? All perfect places for hiding your scientific shenanigans!

Props Department

Pay careful attention to the design of your Video Game Tools. Remember the Rule of Perception; that black cube might be a Skeleton Key for electronic doors or a ghost repelling talisman, but how's the player meant to know that? Making them and their hazards Colour-Coded for Your Convenience isn't a bad idea either.

Costume Designer

It's important that the protagonist have a distinctive look; Rule of Cool should be in full effect (ideally, the PC should be immediately recognisable from the silhouette). However, this doesn't rule out the fact that practicality can have a hand in designing the costumes. Consider making the outfit contrast or clash with the area the protagonist's exploring to play their connection with it (if any) up or down (for example, Metroid contrasted Samus's bulky armour with the organic environment and the insectoid armour of the Space Pirates, while Castlevania gave its vampire hunter protagonists medieval outfits which fit in with the Hammer Horror aesthetics of the castles they explored).

The appearance of NPC characters should reflect their role. As with the player, they should be quickly identifiable (although if they provide some sort of service you could cheat by sticking an icon above their head, but that might break the player's immersion). The Item Shop NPC should look like a merchant (or someone working for one), the weapons master should look like a warrior and the Big Bad should look like bad news (unless you're going for Light Is Not Good or they're in disguise, of course). If they're meant to be members of the same organisation, consider making use of Non-Uniform Uniform in their design.

Enemy design should reflect their role too (e.g. make fast enemies look lean and agile, give charging enemies horns or thick skull plates). If they have specific weaknesses, the player should be able to guess at them, too (e.g. give enemies which are weak against fire a cold pallet or have them resemble flammable objects like wood). The latter should also be consistent (e.g. use the same shade of blue for all fire-weak enemies).

Ideally, every NPC and enemy should be easy to distinguish by their silhouette alone.

Casting Director

In keeping with the advice mentioned above, the cast should consist mainly of helpful NPCs and enemies. A good rule of thumb is that any non-hostile character who shows up, and the player is forced to interact with, must aid the player in some way (even if it's just giving them directions).

This doesn't mean that you can't have the odd Red Herring or random bystander for flavour, but it does mean that they shouldn't bother the player too much.

Sound Department

The most important sound in a metroidvania is always the tune which accompanies an Item Get! (consider the enticing music which plays while Link's rummaging through a treasure chest, or the triumphant fanfare whenever the player finds an item in a Metroid game). It needs to be short, sweet and memorable; the association will do the rest, as long as its tolerable. You can also use a shorter version in lieu of a chime for picking up extra health/ammo and a longer version for when the player picks up something especially cool (like a new piece of gear).

While it might seem obvious, it's important to ensure that you choose the right sound effects. If possible, try to have a different effect for every situation (e.g. different footsteps for walking on different surfaces, different sounds for striking different enemies and surfaces, etc). If you don't have the time or resources to create a full library of sounds, at least try to at least use a "good" sound and a "bad" sound (e.g. a dull thud if the player strikes a wall and a more satisfying smack if they hit an enemy). As with their visual design, enemies should have unique sounds which fit their role (e.g. fast enemies should have short, sharp calls, charging enemies should make a sound just before they charge), or warn of their impending attack.

Finally, never overlook the role that music plays in the player's enjoyment. If possible, there should be separate music for battles and exploration, as well as a specific theme for boss battles (if not a leitmotif for every boss). If you're lucky enough to have an original soundtrack recorded for your game (instead of using public domain and stock music), consider giving the player the option (or the ability to unlock the option) of listening to it separately.

Tropes to keep in mind for your game's music include:

• Critical Annoyance: This can be incorporated into the music to make it less likely to be a Most Annoying Sound. Options include making the music more frantic as the PC loses health, or adding a Heartbeat Soundtrack.
• Most Annoying Sound: This can be hard to avoid (especially for sounds which are meant to warn the player, which usually need to be irritating to some degree), but there are ways to reduce it:
  • The human brain's designed to pay attention to certain sounds (for example, talking^note this is why someone on the phone or loud muttering can be so annoying - your brain wants to follow the conversation, but it can't) - if they play while the player's doing something else, it'll distract, and therefore annoy, them.
  • Sounds which go rapidly up and down in tone or fall between certain frequencies are also generally found annoying (fingernails on a chalkboard being the quintessential example) no matter the situation. Avoid using these for anything but the odd Jump Scare.
  • Repetition can make any sound a nuisance. Looped music should last at least a few minutes and anything that happens more than once every 30 seconds should just have soft sounds (if any) to announce it.
• Soundtrack Dissonance: While it's usually best to make sure the background music fits the action it plays over, this can be used to humorous effect (e.g in a Mundane Made Awesome sequence) or to play with the player's expectations (e.g. ominous music which plays as the player enters a friendly town).
• Variable Mix: If you can implement one, do (it saves you coming up with several new scores for each area and can give the player cues without breaking their immersion), but playtest whatever engine controls the music thoroughly; even the slightest glitch can be extremely jarring. If your programmer, designer and/or composer are separate people, make sure they stay on the same page.

Stunt Department

Choose the abilities the Player Character has (and when and how they're unlocked) wisely. Some possibilities include:

• Broken Bridge: While it's best to avoid too many of these, you can probably get away with one "skill" which consists of activating all the Floating Platforms, opening sealed doors or otherwise changing the environment to remove obstacles instead of giving you a way of getting past them. It's also possible to give the player some degree of control over this (e.g. being able to switch out the level of water), but this can get irritating quickly if the player needs to keep returning to the same spot to keep adjusting a variable (c.f. the infamous Water Temple of The Legend of Zelda: Ocarina of Time).
• Charged Attack: This is a nice, simple skill to add early on to give the player more combat options and add a bit of strategy. There are also ways to make it serve as a "key" for specific obstacles (e.g. breaking down barriers, an energy based charged attack could be used to start generators or light flammable objects, etc).
• Enemy Scan: Giving the player a way to study enemies (and pick up on their weaknesses) can add a bit of depth to the world. Filling the Monster Compendium also gives the player more things to do!
• Falling Damage: Or rather the lack thereof; the limitation of dying if they fall too far makes for a simple Broken Bridge, but it tends to be annoying in exploration based games. Don't make the player endure it for long (if at all).
• Flash Step: Like the various Jump Physics abilities, this can be used for traversing the environment, with the added bonus of being helpful in combat (consider pitting the player against a Bullfight Boss after they pick it up). Remember to give it some sort of limitation (a cooldown's the simplest) so the player can't just spam it.
• Grappling-Hook Pistol: Or some other means of letting the player pull themselves up to higher ground (as well as a means of ripping shields or armour off enemies to expose them). See Bionic Commando (1988) for an excellent implementation of grappling hook physics.
• Jump Physics: The Double Jump (and its cousin the Wall Jump) makes a great ability to unlock early on (or start the player off with), but it's still a viable option for nearer the end (as Dust: An Elysian Tail proved). In Real Life, humans are lucky to jump more than half their height, so in grounded (pun intended) or Science Fiction settings you might want to justify it with some kind of booster, crampons (for wall jumps) or other means of propelling the PC. It can go unquestioned in a fantasy setting or a more classically styled Platform Game. The Mario Bros. series is a good place to look for tips (see Extra Credit below).
• Master of Unlocking: The main strength of the ability to open particular types of doors is also its main weakness; it's Boring, but Practical and not much of a challenge once you've picked it up. Unless you want to incorporate some sort of Mini-Game, limitation (e.g. the key only functions if there are no enemies in the area, or needs some sort of resource) or give the "key" some other use (e.g. Metroid's tradition of making new weapons open colour coded doors), it's best to make this an early skill.
• Transport: Giving the player a Cool Car (or Cool Ship, Cool Plane, etc) can be tricky to balance (there should still be places the player can only explore on foot), but it also gives the player the opportunity to explore areas in a different way and give the vehicle its own upgrades. It also helps take the edge off backtracking in a large game world. However, beware of forcing the player to have to keep travelling back to where they left it; give them the means to summon it (a la Epona) or make sure it's somehow moved to wherever the player needs it.

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Extra Credit

The Greats

Pure Metroidvania

• Castlevania: Symphony of the Night — Along with Super Metroid, it's well-regarded for being a reliable role model for future Metroidvania titles in regards of the gameplay (thanks in part to the super-secret unlockable Inverted Castle) and story (at different points there are dialogues between the protagonist and the supporting characters, but they don't get in the way of exploration).
• Super Metroid — When it was released, it was considered the pinnacle of non-linear exploration. For the best effect, play it (or track down an LP) and then compare it to Metroid Fusion (which, while equally well polished, used dialogue to advance the story).
• Hollow Knight — A modern classic comparable to the above two, and takes plenty of inspiration from both (Word of God confirms other classics as inspirations, such as Faxanadu mentioned below). As a game made in the 2010s, it also shows heavy influence from Dark Souls (also mentioned below) such as the possibility of different character builds affecting your playstyle, losing all your money upon dying, and interspersed autosave points.

Games With Metroidvania Mechanics

• Blaster Master — This is a good example of how a vehicle can be implemented in an exploratory role. SOPHIA (the tank) is upgraded as the player traverses the Overworld from a Side View, but dungeons have to be explored on foot in a Top-Down View.
• Dark Souls — While it's primarily an Action RPG, the exploration element is very similar to a Metroidvania (not unlike its spiritual prequel, Vagrant Story). In particular, note how the game rewards exploration (with hidden items and sequence breaking), but also quite harshly punishes dying (forcing the player to balance the risks and rewards of exploring, since getting killed in the wrong place could cost them all their accumulated souls). It's a great constrast to the aforementioned Hollow Knight: whereas that game is a pure Metroidvania with RPG Elements, Dark Souls is an Action RPG with Metroidvania elements.
• Faxanadu — This demonstrates how RPG Elements can be introduced to a game; the player can use money they loot from enemies to buy better weapons, Power-Up items (like boots which allow them to fly) and keys to open doors with.
• Metroid Prime — The first 3D iteration in the Metroid series. It more or less managed to move the genre's mainstays to a first person perspective. In addition, the first managed to tell a story entirely through logs and Enemy Scan data, with only the occasional cutscene to show off new areas or introduce a boss (later entries added longer cutscenes and NPC interaction).
• Rockman 4 Minus ∞ — This ROM Hack features an Unexpected Gameplay Change to metroidvania for Wily Stage 3. The previous stage's boss, Snatchman, is an Evil Knockoff of Mega Man who steals the first four weapons he uses. In Wily Stage 3, you must defeat the eight robot masters again, but for half of them you get their weapon back, and the other half doesn't give you anything. The maze-like structure of the level, which uses the tiles and enemies of every previous stage, also fits this trope well.
• Spyro: Attack of the Rhynocs — An isometric platformer that is a combination of a metroidvania and a collectathon. It works suprisingly well, making it a great metroidvania game as well as a shining example of how to do an isometric platformer. The game also fufills some of the potential subversions on this page.
• Super Mario Bros. — While lacking in most Metroidvania mechanics, the Super Mario Bros series is a masterclass in Jump Physics. Pay close attention to the way the jumps in all but the earliest games take into account the player's momentum and allow them to control how they fall in the air. See this video for a bit of detailed analysis.
• Valkyrie Profile — The dungeons play much like a classic Metroidvania, with abilities being acquired and used to traverse a sidescrolling environment (albeit with enemies which take you to a turn based battle screen, instead of ones you fight in real time).

The Epic Fails

• Castlevania II: Simon's Quest — While it was the first game in the Castlevania series to actually be a Metroidvania, it's a masterclass in how not to do a lot of the genre's mechanics. It enforced a lot of backtracking (when each screen transition involved Loads and Loads of Loading) and grinding for the sake of padding the game (the only way to heal was to return to a town, the only way to buy items was with hearts, which were lost after dying), and has annoying audio that interrupts as the game shifted (randomly) from day to night. See this video by Egoraptor for an in-depth analysis of its flaws.
• Metroid: Other M — Its main failing (as far as gameplay is concerned) was moving too far towards a narrative structure, breaking the rule mentioned above; never let the story interfere with gameplay. Half of the areas are designed to be traversed in one direction, specifically the way the player goes when following the story.^noteSectors 2 and 3 suffer the most from this, as both are two loops that have a couple of interconnecting areas. The game frequently locks doors behind the player, sometimes just to prevent the player from even thinking about doing any side exploration at that point in the story.^noteFor example, after defeating Ridley and returning to the Hub, the door to Sector 3 locks behind Samus. And the doors to Sectors 2 and the Main Sector are both locked. Because Samus must follow The Deleter into Sector 1 right now. Movement and ability upgrades (as opposed to collectables like missile expansions) are in all but two cases dispensed at times dictated directly by an in-story entity. Samus (and by extension, the player) has them, but can only use them when she is explicitly told to do so by a CO (who also tells them where to go), robbing the player of their exploration. In contrast to Simon's Quest, this serves as an example of what happens when you take the Metroidvania mechanics out of a Metroidvania, rather than add them to a game where they don't fit.

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