New Leaf offers a ton of new features which should keep you busy for quite a long time.
As mayor you have the power to control the town and build even cooler stuff in your town including a café, street lights and even a tower. Like past Animal Crossing games if you've played the series before you can name your town as soon as you start your own new game but if one or more players decide to play New Leaf they can only live the in the town you've made they can't create their own town for this.
Using the analog stick to move around or either hold down B,R or L to run, you can use the directional pad to switch to a tool such as a fishing rod, net, and slingshot. If you press both L and R you can take pictures and those pictures can be saved on your 3DS camera, using the A button to talk to other town people, or entering a building or purchasing something. The X button can also be used to close or open your pockets where you can use the touch screen to switch items back and forth or even designing your own clothing.
While running around your own town you can dig up fossils, fishing or capture bugs and most of these can either be sold in the pawn shop which can give you lots of bells or they can be donated to the museum. In New Leaf once you've gotten your new house you'll have to pay your own mortgage for your house once it's fully paid you can either keep it the way it is or make your house bigger but you'll have to put in another mortgage for that. As Mayor Towns people will request what they want in the town but to get all this you'll need money to build these projects.
What really shines about Animal Crossing New Leaf is the graphics look really cute and charming to look at. Even though they speak in gibberish they still can make you laugh half the time, the fun part is that you can change the town theme music to anything you want and hearing different theme tunes from other town's people can be funny. Another fun thing you can do is design your own town flag and clothing which can be fun especially if you want any of your clothing in the fashion shop where other players online can add to their designs.
There is online support where you can head to the post office to pick up a special present which happens once every 2-4 weeks so you may want to check sites like Facebook to know. The streetpass for New Leaf is another clever thing about it is if you get streetpass by another 3DS and they have a copy of the game, they can show off their home. If you want to visit a friend's town you can either do this online if you have good Wi-Fi or if you are out with a few friends can play local up 2-4 players where you can visit other towns or play some multiplayer games.
If you have a 3DS this is highly worth checking out and will make you come back for more and more in the delightful world of Animal Crossing, like I just said above this review it's more fun playing with friends.