The first thing to realize is that there are different genres (kinds) of pet games, which have different feature sets. It's very helpful to any game designer to have played a variety of games so they remember experiencing a variety of features and can pick from that "mental toolbox" which features they want their own game to have. If you have only ever played one kind of pet game, you would have difficulty trying to make anything other than that same type of pet game. If you want to make that kind of game, that's fine, though background knowledge of a variety of games would help you avoid designing a game that's just a rehash of something that already exists. So, I encourage all designers to play a variety of games, the same way writers should read a variety of fiction and artists should look at a variety of art. But it's ok if you already have a specific type of pet game in mind because you want to make a game similar to your favorite, or combining features of two or three of your favorites. It's also ok if you just know that you want to make a pet game, but not know exactly what kind yet. Figuring out which kind you want your game to be is the first step in creating your own game design document!
There are different kinds of genres. "Pet Game" is itself a genre, specifically a theme or motif genre. Fantasy, science-fiction, and sports are also theme genres. There are art genres, like 2D vs. 3D and anime style vs. western comic style. There are story genres, like horror games and romance games. Then there are gameplay genres, which is what people usually mean when they talk about genre: RPGs (role playing games), sims (simulations), MMOs (massively multiplayer online games), and others less commonly seen in the realm of pet games, such as adventure games, FPSes (first person shooters), and RTSes (real-time strategy games). The overall point of this section is for you to start writing your design document by listing what genres of different kinds apply to your game. The idea is that a person can pick up your game design document and in the first few sentences you will give them a concise and clear description of your proposed game.
Specifically you are going to fill in the blanks in this sentence: "[NameOfGame] will be a [2D or 3D or ?D] [optionally name the art style, e.g. anime] [singleplayer or multiplayer] [VPS/RPG/SIM/etc.] game where the player has [a small number or a large number] of [type of pet if you know it already] which which they do [combat or other main activity of the game]." Sorry if that looks confusing. Once you plug all the information in it will look like something sane, e.g. "Sunandshadow's Fish Game will be a 2D realistic-art singleplayer RPG/sim where the player has many fish which they use to battle and capture more fish, breed in a fishtank, and craft into fishscale armor, weapons, and potions." Or, "Sunandshadow's Dragonrider Game will be a 2D anime singleplayer interactive story game where the player has 6 dragons they can attempt to befriend and partner with in dragonrider training class until one of the dragons agrees to permanently bond with the player and accept him/her as their rider." Or "Sunandshadow's Virtual Pet Site will be a 3D Spore-style multiplayer VPS where the player starts with one pet of the most basic type and, using it to explore and breed, collects all possible pet variants."
The Name Of The Game
You might happen to have a name in mind already; if so, cool. If you don't have an idea for your game's name yet, that's also fine. This section is not about brainstorming an awesome title which elegantly expresses the project's identity and grabs the attention of the project's target audience. Actually, names are often changed as a creative project develops, and are often one of the last things to be decided. It's almost impossible to think of a great name at the beginning, when you don't fully know yet what the project will be. No, what we want here is a functional working title. Something simple and handy you can use to name the file, discuss the project with others, and later use a search and replace to automatically put the game's real name in all the right places. I recommend something like Jane's Pet Game or Dragon Breeder Game or Pokemon Clone. So just pick something and fill in that first blank. Also, create a new document, name it Jane's Pet Game Design Document or whatever, then copy and paste that bolded sentence into it so you can fill in the blanks there. Unless you prefer to use a pen and paper, that's fine too.
What Are You Doing With Those Pets?
Pet games (or pet monster games, monster capturing games, monster breeding games, livestock ranching games, horse riding games, etc.) are characterized by the player's enthusiasm for some kind of creature. They don't have to be literally animals, but instead anything that can be presented as animal-like, including plants, robots, alien creatures, magical beings, or virtual creatures. Pet games could be divided into those where the player interacts a lot with one or a small number of creatures vs. where the player collects or breeds a large number of creatures, selling unneeded ones, or even slaughtering livestock to harvest crafting resources. Which of those are you more interested in creating? Approaching the question from a different angle, pet games could be divided into games where the pets' main role in the game is combat-related vs. those where it is something other than combat. Does one of these two types sound more like what you want to make? When you combine these you get four of the most common kinds of pet games:
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1. A game where you own one or a few companion pets (or you are an animal or small group of animals) and you fight alongside or through them.
2. A game where you fight to build up a collection of pets which become your army or workforce (units in your combat squad, cards in a deck, or part of your home base producing stuff for you).
3. A game where you care for one or a few pets and compete with them.
4. A game where you have a farm or ranch where you raise many pets to sell, compete with, or build up to a complete collection.
Is one of those what you want to make? If not, here are a few less common options, and of course it is possible to mix and match:
[indent=1]5. An interactive story game where you talk to creature-characters, trying to befriend them or solve problems related to them.
6. A game where each pet is a challenge because they need to be healed or tamed before they can be passed on to a permanent owner.
7. A babysitting game where you must take care of the needs of several pets as fast as you can to keep them happy.
8. A world simulation where you experimentally create creatures and see how they survive in the wild.
9. Add your own!
2D vs. 3D
Art type is a challenging topic in game development because it is 1/3 personal preference, 1/3 dependent on what resources you have available because artists and game engines alike tend to only be good with one kind of art of the other, and 1/3 functionality because while some gameplay works fine with both approaches, a few kinds of gameplay work much better with one or the other. Since those thirds are like apples, oranges, and, plums, it's quite difficult to balance them against each other if they conflict. All you can do is try to figure out if some factors are more relevant than others. For example if you, the designer, really hate one of the two styles and don't want to put time and effort into developing a game that will have that type of art, that probably overrules any other issues. Or if you intend to be the primary artist and are only good at one of the two types, or you intend to be the primary programmer and already own a license for a game engine that is focused on one of the two types, that's also a strong argument for which you should go with. Or, if you have a strong idea of some gameplay you want your game to have which is incompatible with one of the two types, that's another strong argument. It's convenient to the development process to decide early which type of art a game will use, but if you really are stuck between the two options it can be postponed until more data is available to reevaluate the choice. There are also a few less common options like 2 1/2 D that you might want to research if the two straightforward options aren't working for you. Fortunately the question of art style (as in things like realism, anime, western comic, gothic...) is a simpler issue because it has basically no functional difference, just personal taste and what your available artists have experience with.
Singleplayer vs. Multiplayer
Two main categories of computer games are online multiplayer games, and offline singleplayer games. The big difference between these two types is that in singleplayer games the game's primary activity is always something the player does against computer-generated opponents, whether these are monsters or something more abstract like a time limit. In multiplayer games, on the other hand, competition against other players or cooperation with other players is a significant part of the game (even though the majority of the player's time within the game may still be spent of single-player activities). A few games have a limited online component, such as phone and Facebook apps where the only things the player can do online are buy cash shop items and send presents to neighbors; these have mainly singleplayer gameplay so I will include them in the singleplayer category. Do you know whether you want to make a multiplayer or singleplayer game?
Multiplayer Game Genres:
Virtual Pet Sites - Pet Sites are characterized by having their primary multiplayer activities include forum posting and trading items or pets with other players. Some VPS games include a breeding system, and if they do it is commonly possible to use other players' pets as breeding stock. Some games encourage the player to collect pets or other collectibles. Some VPS games include a minigame arcade; if they do this is typically the main source of player income within the game, and players may compete for high scores at the games. Some VPSes include a clothing system, either for pets or human avatars. VPSes are the pet-themed version of social gaming sites, which are usually built around a forum with a customizable avatar and clothing system. This system is intended to facilitate player socialization by allowing players to present a carefully-chosen visual representation of themselves to others, and regularly update this visual representation to reflect holidays and other social events.
Minigame Arcades - Minigames are games which take a short time to play. They consist mainly of speedpuzzle games (Tetris, Frozenbubble, Pouyopouyo), solitaires (cards, Mahjongg, Minesweeper, Hangman, boardgames against a computer opponent), and arcade games (beat-'em-ups, shoot-'em-ups, bullet hells, pinball). In many some cases it is possible but rare to win; in other cases it is impossible to win, instead the player is scored on how long they survived or how many targets they shot or bonuses they collected before losing. A minigame does not have to have a forum or other social component; sometimes they are purely ad-supported and have no cash shop or membership. If a minigame arcade is combined with a social forum such as VPS the arcade is usually the method by which players can earn a daily income of game currency to spend on pets, clothing, or similar items. Minigames may not be terribly memorable or artistic, but they are convenient from a site maintainer's perspective because if one breaks or is disliked by player it is not related to the others and doesn't spoil the players' enjoyment of them. Arcades are also easy to expand by adding new minigames, as opposed to larger games where new content must be integrated and balanced with existing content.
PvP Pet Competition Games - PvP (player vs. player) games are those where the main multiplayer activity is dueling other players; possibly in combat but non-violent activities like racing, show jumping, agility, dressage, or beauty contests are also popular. One of the main goals is to earn a high rank in the competitive league of all players. Another goal may be to have the highest personal score on a particular course compared to your friends or other players who attempted that course during the current week or month. These games come in two flavors, fast-paced for those who crave adrenaline, and slow-paced for those who prefer strategy and patient persistence. The fast-paced kind has a main activity of driving the pet at high speeds while avoiding obstacles with quick reflexes (Or more rarely, fast-paced RTS combat between the armies belonging to two players.) The slow-paced kind is a sim or RPG where the main activity is increasing pet stats through training, breeding, or interacting repeatedly with an individual pet; in these slower-paced PvP games the competitive activity is either automated or turn-based instead of real-time. Both flavors of PvP game may have a singleplayer campaign or series of quests which teach the player how to play and may allow the player to earn higher levels and increased stats for individual pets or for the player's infrastructure. (Infrastructure is the property, tools, and abilities the player uses to produce competing animals: their ranch or other property, appliances and outbuildings for storing and breeding pets, training pets, or crafting useful items, their ability to breed higher-potential or rare baby pets, and their ability to modify pets.)
MMORPGs - MMOs are games where hundreds or thousands of people interact within an explorable virtual world. Whether the game uses 2D or 3D graphics the key element is that friends can, in realtime, see each other doing stuff within the world. RPGs are fighting-focused games where the fighting is strongly effected by stats; the main activity of the game is increasing these stats through leveling up and getting better gear. Progress through the game is typically guided by NPCs (non-player characters) offering quests, but the player is usually free to wander anywhere they don't immediately get killed by higher-level monsters. The most common type of combat is realtime involving spellbars and cooldowns, but many other types of combat are compatible with this type of game, from simple turn-based to turn-based tactical to realtime 3/4 overhead to realtime sidescroller/arcade/platformer, and even racing combat where racers can attack each other during the race. Please see the combat section for more details. Some MMOs are almost completely focused on PvE (player vs. Environment, where environment usually = monsters) combat. Normal difficulty monsters are found by single players or pairs of players in the main game world, while instanced dungeons are populated with elite (high-difficulty) monsters and bosses that require teams players to work together. Other MMOs have a focus on PvP, whether between individuals or in teams of 5 or more. Singleplayer PvP involves dueling other players for personal gain; group PvP can be simple team duels where the last player alive determines which team wins, or can be a more complicated activity of territorial capture by either NPC factions that players join or player-created clans/guilds. However PvP is structured, each player earns a PvP rank by their performance, and improving this rank is a goal and a source of pride. Both PvE and PvP are the main source of player income in games featuring them.
FPSes - I have not actually seen a pet-themed FPS, so I'll speculate on what one might be like. One possibility is that different pets might correspond to different types of guns, or perhaps biological armored suits that happen to include guns, or animal forms the player could shapeshift into which would happen to include distance attacks. The player would have the ability to bond with (or equip) one animal at a time, and which animal was equipped could affect range, firing speed, power, special effects like poison or freeze rays, and maybe things not directly related to shooting like the player's size, running speed, armor, healing speed, max health, jumping ability, etc. There are single-player FPSes, usually those are very similar to either an RPG or a fast-paced PvE racing game. Multiplayer FPS games are more different from MMOs and fast-paced PvP competition games because of the emphasis on short, intense interactions between 4-12 people and their environment (because the environment typically contains weapons, ammo, and healing items that the players have to scrabble for while avoiding being shot). Some FPS games have battle royale rules, meaning all players are against each other and the last one alive wins. Other FPS games have team play, often inspired by capture the flag, with death being a temporary setback from which players respawn until other one team or the other captures the flag (or destroys the other team's base, or whatever the specific goal is).
RTSes - Real-time Strategy Games typically have BOTH a singleplayer campaign and a multiplayer system for allowing 2-4 players to duel. The closest an RTS gets to a pet game is probably where the units are all creatures, and the buildings are either also creatures or are designed to feed or breed creatures. SimAnt is a fairly clear example, while the Zerg race in Starcraft may require a bit of squinting to see as an army of the player's pets. RTSes are all about building up infrastructure and climbing a tech tree, as described in the entry on sims. But in an RTS the play has to do it as fast as possible while being attacked by enemies, and the goal of PvP duels and most singleplayer missions is to exterminate the enemy from the map. Sims on the other hand are generally slower-paced, and instead of extermination sims are usually about becoming the best pet-breeder or similar profession, and earning a lot of money this way.
Singleplayer Game Genres:
RPGs - Single-player RPGs typically lack the focus on character appearance customization that MMORPGs often have. Instead single-player RPGs come in two flavors: J and W. J stands for Japanese and W for Western, but that was a historical division that is no longer accurate. These days both types of RPG can be made anywhere. Instead it's best to think of jRPGs as those which have a strong story and pre-created characters and quests, while wRPGs are those in which the player creates the playable characters and the game can generate semi-randomized quests, maps, and/or NPCs to make the game extensible and replayable. In jRPGs the player's progress through the game's story and world is regulated mainly by quests and puzzles which must be solved to unlock the player's ability to move to a new physical are of the game. In wRPGs the game is usually less linear, with the player free to wander anywhere they can stay alive. Both games have a focus on 1-10 playable characters and their use in combat, which can come in all the varieties listed under MMORPG. Singleplayer RPGs by definition cannot have PvP, so all play is PvE, unless the game has limited multiplayer functionality which allows dueling outside the main context of the game. But the main activity of the game is fighting monsters and bosses. The overall goal of this activity is to become the best fighter in the world and beat the biggest bad guy in the world.
PvE Pet Competition Games - These are singleplayer versions of PvP Pet Competition Games. As with singleplayer versions of strategy games, singleplayer competition games are often organized in the form of a campaign, a sequence of increasingly complex and difficult competitions which will eventually result in becoming the world-wide winner of whatever the particular competitive activity is. Like the PvP version the PvE version is split into fast-paced activities like racing and flying games and slow-paced activities like pet shows of the beauty contest variety. This genre is the one that most commonly tends to be confused about whether it is a game or a toy, though VPSes and sims may also suffer from this confusion. This causes problems both during development and for players of the finished game. See the entry below about Virtual Toys for info about avoiding this mistake.
Babysitting Game or Time Management Game - Other pet games often include a babysitting segment for raising young pets or breeding pets. Babysitting games can also be minigames. Technically they are a hybrid between a speedpuzzle game and a sim. A time management game is the non-combat version of an RTS, though in most time management games you control one unit rather than an army of units. What happens in a babysitting game is that the pets have happiness, health, cleanliness, sleepiness, or similar gauges. And these meters will get lower until the pet is very unhappy or dies, if the player does not intervene. Either the player can select the pet to see all of its gauges, or the pet will emote any need that crosses into the danger zone, or both. Emoting can be done by an emoticon symbolizing the pet's need appearing above their head in a thought or speech bubble, or it can be done by the pet's facial expression and/or body language changing to express their need, along with other visual effects like "stink lines" rising off a dirty pet. In some cases pets do not have health gauges; Lemmings is a classic example. The pets move of their own volition and often encounter fatal obstacles. The player must use some pets to solve the level's puzzle while keeping enough pets alive to lead them through the final gate to safety and satisfy the level's victory condition. When babysitting is the main activity of a standalone game the game is typically organized into a campaign, and each level of mission has a time limit. Time management games have a similar dynamic where the player runs around as fast as they can trying to fulfill a variety of needs. These goal of the game is not to maintain happiness though, it's probably to grow, breed, or craft something which can be sold for money, as in a Tycoon game.
Sims and Tycoons - Some Pet Competition games and RPGs overlap with sims, in that they can all include breeding, collecting, and training pets, and amassing wealth, levels, and/or stats and special abilities tied to level. Sims and RPGs may also both include crafting and building up an infrastructure by climbing a tech tree. Where RPGs have an overall goal of becoming the best fighter in the world, sims and tycoons usually replace this with a goal of becoming the best farmer or breeder or collector or crafter in the world. As the player gains experience they usually unlock new resources and special abilities related to this profession. Tycoons are a subgenre of sims; there's no real difference between the two except that tycoons have more of an emphasis on making money via selling the results of your sim-labor, while non-tycoon sims sometimes don't even have a currency system. Sim games usually have tech trees. A tech tree is a structure where the player puts effort into unlocking or mastering low level abilities, which are prerequisites to unlocking or mastering higher level abilities. For more details see the crafting section below.
Adventure Games and Interactive Story Games - Adventure and interactive story are actually two different genres, I'm just combining them here because they are so often seen together. Both of them typically lack combat, though they can be hybridized with a kind of game that has combat (for example the Zelda series are action-adventure hybrids). Both of them are typically singleplayer because, like sim gameplay, puzzle-solving gameplay is very difficult to make multiplayer without interfering with what makes it fun. The difference between these two genres is: Adventure games have physical puzzles that the player solves by flipping switches, turning knobs, sliding things along tracks, using pipes to move fluids around, igniting fires, and that sort of thing. Interactive story games mostly involve talking to other NPCs in a form of interaction called a dialogue puzzle, where the player can choose from a list of options what to say or do, and the choice made affects how the NPC decides to act, which in turn sends the plot of the game in one of a few different directions. In fact an interactive story game as a whole can be seen as one big puzzle where the player tries to carry out the right steps in the right order to get the best possible ending; many interactive story games expect the player to play through the game more than once the same way adventure games expect the player to need to restart puzzles if their first attempt at solving the puzzle turns out to be the wrong strategy. So both genres are about solving puzzles, the difference is just whether the puzzle pieces are physical objects or people. And it's common for games to have puzzle pieces of both types, thus making the game a combination of the two genres. Where do pets come in? Well, pets can be puzzle pieces, such as in a game about herding sheep through mazes. Animal-forms or summons can be puzzle solving techniques, such as a game where the player changes into a spider or summons a spider to weave a giant spiderweb that acts as a net to solve a puzzle, or the player changes into a bull or summons a bull to push a heavy object that they otherwise couldn't move. Or the player could be responsible for a space ark full of animal characters and have to matchmake between the animals so they are ready to produce lots of baby animals when they land on their target alien planet. There are all sorts of ways a game could be about solving complex puzzles involving animals.
Virtual Toys - Virtual Toys resemble games, but they generally have no goals or victory conditions. "Pet games" which are actually toys include the software portions of Tamagotchis, Furbys, and HexBugs, as well as various desktop pets and virtual fishtanks/fishponds. In the realm of non-pet games, Minecraft is the most notable example of a virtual toy in the past few years, though it has grown more game-like features (such as deadly monsters) since it was first created as a virtual lego-like toy. As a designer it's important to be aware of whether you want to make a game or a toy, since players who expect one will be disappointed if they get the other. Games and toys are both fun but not really in the same way, and software which has half game features and half toy features can be confusing and frustrating to the player - in other words, they can fail to be either kind of fun.
