Exhaust all the dialogues in the desert areas, including your father's calls.
Activate the minibang event. You'll know when you get it.
Beat Saladino.
Surf the sandstream without getting hit.
Discover the skeleton in the basement of a house.
Solve all the puzzles without resetting them with the help of the NPC.
Enjoy a nice view.
Give a rock to a crablinger.
Exhaust all the dialogues in the desert areas.