Animal Crossing: Wild World features a very minimal plot. The objective of the game is to pay off a debt to Tom Nook, who allows the player to move into a house he owns. If the mortgage is paid off, the player's house will expand until upstairs, left, right, center and back rooms are included. This is slightly different to the Nintendo GameCube version, in which the finished house only consisted of a basement, a main room and an attic. While paying off a debt, the player can do a variety of optional tasks, including interacting with other villagers and filling the catalog of the things you have, like furniture, fish, clothes.

Animal Crossing: Wild World makes use of several of the Nintendo DS' features, including the touch screen, dual screens and internal clock. The touch screen is used for menu navigation and interacting with the surrounding area, including movement, using tools, talking to other villagers, entering buildings, picking up items etc. The dual screens are used to display the overworld on the touch screen and the sky on the top screen, which varies depending on the circumstances. 

HINTS

MONEY

Rocks

Keep hitting rocks with an ax or shovel until finding a special one that gives a bag of Bells. Keep hitting it until the bags stop appearing. Note: This only happens once per day. 

Take out your shovel and hit rocks with it until it spits out Bells. Keep hitting it. It can go up to 20,000 Bells. If you want to get all the bells, dig three holes away from the rock, and hit it. This will push you back but you will still hit the rock because the holes are there.

Use the following trick to get more money from rocks when you hit them with a shovel. Dig a hole behind and on the sides of you. Then, hit the rock. If there is money in it, it will pop out. Because you have holes around you, they will stop you from moving away and rebound you back to hit it again. You can get up to 2,000 bells for your last hit. Note: Do not put holes anywhere else or the money bags will not be able to come out and you will not get all the possible bells. You can only get bells from one rock per day.

Here's a video of this popular game: