Pokemon Rumble World is the newest entry in the Rumble franchise. It's free-to-play with microtransactions like Shuffle, but the paying nature of the game is less obnoxious.

Rumble World 101:
>Pokemon in this game have 1-2 moves. They cannot equip items or evolve. They don't have abilities, etc, you get the drill. You have to obtain the evolved forms yourself. However, they can Mega Evolve.
>The goal of Rumble World is collect strong Pokemon and beat up as much Pokemon as you can.
>Defeat a Pokemon and it may 'drop' and you can use it. Boss Pokemon are harder to 'drop'.
>PokeDiamonds are the 'Jewels' of Rumble World. You obtain them from doing the King's challenges. You can also buy them with real cash.
>Balloons unlock stages in a certain world. For example, the Sapphire balloon unlocks the Sapphire Sea's stages. You buy them with PokeDiamonds. When you want to enter a stage, there is a roulette system where you stop the roulette and a stage is picked by the roulette.
>When you enter a stage the balloons have to be inflated again, which means that you have to wait a certain period of time before going to another stage using that balloon.
>The King will set you challenges ranging from 'defeat x Pokemon' to 'protect your Mii' to 'win a Battle Royale'. You get gems for meeting extra targets set in the challenges. For example, completing a Battle Royale with Electric Pokemon only.

If there is anything else needing to be explained I wi;l explain it