Starting Out
As the game opens, you'll see Mario and Luigi perform a brief fight scene. Pressing 
once will make Mario and Luigi disappear to reveal three turtles running across the screen; then, choose one or two players and hit again to reveal the game map. A small window will appear in the middle of the screen, indicating the player and the starting lives. Navigate to level 1 and hit 
to start.
Map Features
The map features many rectangles marked with a level number. You cannot get past a rectangle that marks a level you have not conquered; however, there is a shortcut on the map that lets you skip levels 3 and 4. Also, when you conquer the castle level, the lock will disappear, so if the game becomes over, the lock will still be gone, so you can skip directly to level 5. The mushrooms featured on the map are toadstool houses. When you enter one, a citizen of the Mushroom Kingdom will greet you. You will be presented with 3 chests, each of which can be opened by pressing 
to reveal a power-up. However, you can only open one chest for each house, and the power-ups switch around for each house. The Ace-marked rectangle is a aligning challenge. When you enter it, you are presented with three different power-ups: a flower, a mushroom, and a star. The three power-ups are divided into three sections, which are rapidly moving horizontally. You must hit while the sections are aligned into one power-up. If you properly align a mushroom, you get two extra lives; a flower, three; and a star; five. The brown figure toward the end of the screen is a Hammer Brother. If you touch him, you will be drawn into a mini-level that features the Hammer Brother on top of a platform made of brick. The best way to defeat him is to run underneath him and jump up, bumping the brick under his feet. This will kill him. When he dies, a toolbox will appear somewhere on the screen. Touch this tool box, and it will open to reveal a star power-up. The brick to the utmost right will sometimes reveal a mushroom/flower power-up. Very rarely, the Hammer Brother will be replaced by a ghostly ship. This ship is full of coins, but at the end leads to a room with two Boomerang Bashers on either side of you. The star you receive, as well as any power-ups you receive at any location other than a regular level, will go into your "pocket". This pocket can be accessed by pressing at the map. The castle at the very end will show you to your last quest of that "World", which is to rescue the Magic Wand from the terrible Larry Koopa. When you complete that, you will be shown to the next world, which is a sandy territory. This World follows the same pattern as the world before it, but adds additional dangers.
Information Bar
If you look at the bottom of the images provided above, you'll see a light blue bar. This is the Information Bar, which provides the statistics important to the game you're playing. Let's take a look, shall we?
Indicates World: This shows which of the 8 worlds you are on. For a preview of all eight worlds, see the Walkthrough.
Speed Meter: This shows how fast you are going. To fill up the meter, hold down and move to the left or right for a while. Advanced players will be able to fill the meter simply by running back and forth. If the meter fills up all the way to the "P" symbol, Mario or Luigi will have the capacity to make amazingly long jumps. When this happens, they will hold their hands outward in a position resembling airplane wings. If they are wearing the Raccoon or Kanooki suit when this happens, they will be able to fly for a short distance, if you press the repeatedly. Normally, pressing the button while wearing one of the suits will simply slow your fall.
Coin meter: The coin meter simply shows the amount of coins you have obtained throughout your travels. You can get coins either be retrieving them from "?" blocks or snatching them out of mid-air. When the meter reaches 99, the next coin will send it back to 0 and give you an extra life.
Cards obtained: You get a card at the end of every level by jumping up and bumping the block with the flashing power-up pictures. The power-up that is displayed on the giant block when you hit it is the one that will appear on the card. You get extra lives from the cards you get. If you get 3 stars, you get 5 extra lives; 3 flowers, 3 lives; and 3 mushrooms, two lives. Any other combination will get you one life. The cards will be cleared from the Info Bar when you get three of them.
Extra Lives: This displays the amount of lives that you have other than the one that you are playing with. (To find your actual number of lives, just add one to this figure.) For this reason, you can have 0 lives on the meter, and still be playing. The "M" is changed to an "L" when you play as Luigi in two-player mode.
Score: This is simply the amount of points you have gained throughout the game.
Time: For every level, you are given a certain amount of time to complete it. This timer ticks away the seconds you have. If the timer reaches 0, you will be sent back to the map and lose a life.