You could use my PIP Actor Class (picture in picture class) to create the minigame object in your world. It will allow your main world to control the running state of the minigame. You would code the minigame as if it were a separate level and the PIP Actor object will display it as an actor object in your main game world.

Ah..Thank you! I see your code, but I'm afraid I'm still a bit confused.. T-T Um... How exactly would I code it as a separate level and use the PIP Actor? Also, how would I make it so the minigame would only appear if the player lands on a certain square? Thanks again.

Create a subclass of World and call it MiniGame. Code your minigame as if it was your project (ignoring anything outside the minigame). As far as making is show when the player lands on a certain square, you will need to supply the relevant code (main world class code from first line down to at least the constructor (or prepare method) and the player class).