Pokémon Rumble World is an action brawler game set in a kingdom full of toy Pokémon. The king of the realm asks the player (who is represented by a Mii) to help him collect more toy Pokémon. A wizard appeared before the king and boasted about how he has 11 different types of Pokémon toys in his collection, while the king only has one (a Pikachu). The king requests the player then go out and find and catch as many different types of Pokémon as possible so that he can confront the wizard.
In order to catch new Pokémon, the player must buy hot air balloons to travel to different areas where Pokémon toys appear. Each balloon costs Poké Diamonds, which is the games currency. Poké Diamonds can be bought with real money, or earned through gameplay.
Once the player buys a hot air balloon they can travel to certain themed levels (forest, fire, water, etc) to catch Pokémon toys. The player is given a sub selection for each balloon that spins like a roulette wheel. The player hits stop and it will land on one of the selections and then take the player to that map.
There is also a chance to get something called 'Fever' mode or 'Super Fever' mode on the roulette select screen. During these all the levels on the screen will go up in rarity, meaning different and sometimes rarer Pokémon toys will appear.
During the levels the player controls a Pokémon toy and uses it to attack other spawning Pokémon toys. This can be done by either just ramming into them and auto attacking with the Pokémon's default skill, or by hitting the A or B button. The B button connects to a second skill, which not all Pokémon have, while the A button connects to a default attack. By hitting the buttons on your own, the player is allowed to have some sense of tactics, particularly when using longer ranged skills such as the bug type move Pin Missile.
To catch a Pokémon toy the player must first defeat a Pokémon toy. Upon its defeat, the Pokémon will either turn into coins or appear on the ground. The player can then walk over the coins or the Pokémon toy in order to collect them. Coins are another in-game currency that cannot be purchased using real money.
At the end of every level there is a boss Pokémon that must be defeated in order to exit back to the main castle map. The boss Pokémon will spawn a large amount of minions continually until it is defeated. After its defeat it will drop a large amount of coins, and the player has a small chance that the boss Pokémon will be able to be caught. The player then exits the stage by walking up to the balloon that appears on the stage, which takes you back to castle.
Any Pokémon toys caught will shown up as the king checks them over, and gives the player a chance to look over each ones skills and base stats.
The player must then wait (or pay Poké diamonds to bypass the wait) for the hot air balloon to reflate before using the balloon again. This can take anywhere from 25 minutes to 5+ hours, depending on the balloon.
To start, the player can only have a small number of Pokémon at a time. This number can be increased by buying Poké Houses from the in-game shop. The first few houses cost 2 Poké Diamonds, with the prices steadily increasing over time.
Players can also purchase clothing items for their Mii characters, as well as borders & backgrounds for your Miis profile (which can be sent to other players via Street Pass), and items to help boost your Pokémon toys stats. Some items can be purchased only with Poké Diamonds, while others can only be purchased with coins.
Once the goal of 11 different Pokémon toys is reached the player is given the chance to confront the wizard, an defeat his Pokémon horde in battle to defend the kings honor and crown. This plays out just like the other stages, with the exception that you can not catch any of the Pokémon you defeat and that there are some new obstacles, such as cannons shooting at you and cages hidden in the ground that trap you for a short amount of time. Upon defeating the wizards boss Pokémon (a Mega Alakazam), the king will thank the player and tell them that he will call on them when he needs help. At this point, the king will start giving out a new story quest once a day. The only way to skip the waiting requirement and unlock the next request is to have a high enough crown rating.
Crown ratings are based on how many different types of Pokémon you have caught. The higher your crown rating, the faster you can make it through the games main story and unlock new items.
Poké Diamonds can be obtained through the games daily quest system that gives the player a chance to earn around 11 Poké Diamonds a day by completing certain tasks within the Kings Request quests. Examples of some of the quest requirements are to beat the level within a certain amount of time, use a super effective move within the quest, or break a certain amount of items within the quest level.
The Kings Request quests can be repeated as many times as the player wishes, even after they are completed. However, the player will only earn Poké Diamonds once for each quest requirement.
The Street Pass feature allows people whom you Street Pass with that also play this game to appear within the your game. The Street Passed Miis will sometimes offer the player to pay either coins or Poké Diamonds to go to new areas without using a balloon, or they may appear within a level. If the player rescues the Mii within the level, it will follow the player around giving buffs or healing items until the level ends. Miis also have HP bars, so they can be defeated. Players will not earn an extra bonus if the Mii is defeated before the end of the level.
Once per day, players can call people from the internet and have them appear in their game as though they had Street Passed with them. This helps players who aren't able to get many Street Passes to access all parts of the game.