When you are on the world map if you highlight a world and press
then
you can see what the missions there are for that world.
In order for the mission to count you must be traveling to the world not away from it.
Now, the easiest world and quickest world to do this with is Wonderland, and you can finish all 3 of them once you have your second trip to Traverse Town, when Cid begins selling you Gummi pieces.
Mission 1- All you have to do is score 120 points. Pretty simple. You get 1 point for every enemy you kill, obstacle you break, or item you pick up. Honestly pretty hard to miss.
Mission 2- You have to use haste more than 5 times and arrive with no damage. You can buy a haste block from CID for 1000 mummy as soon as he opens shop. Then equip it to your Gummi ship and travel from Traverse Town to Wonderland using
to boost when it charges up at least 5 times and avoid enemies. Pretty simple.
Mission 3- You have to pick up 40 Gummi pieces while traveling from Traverse Town to Wonderland. Another simple one. When an enemy dies they drop a Gummi piece. Just kill atleast 40 enemies and pick up the pieces they leave behind.
I hope this guide helps everyone out while they’re enjoying this masterpiece of a game!