The first, and most important, tip of conquering the worlds of Super Mario Bros.: Know your enemies! Learn the diabolical personalities of all your opponents. Each enemy has a different attack pattern. You'll attain a high score only by judging your enemy accurately, and adjusting your attack to its behavior.
The Koopa clan is made up of 17 species. The only thing they have in common is their desire to get Mario and Luigi! They all have different ways of accomplishing this goal. It's important to know all of their attack patterns. Watch out, some of the Koopa clan are indestructible.
Goomba
These are the "baddies" that betrayed the Mushroom Kingdom. They go for Mario in a straight line, and are easily trounced with one attack. Fireballs, a quick stomp, or a hit from below will do it.
Koopa Troopa
The green Koopa Troopas always charge Mario in a straight line, and will drop down from the ledge they started on. The red Koopa Troopas pace back and forth within a given area, and will never fall off of a ledge unless kicked. Timing is everything! A stomp stops them, but not for long. Stun them with a jump then kick-and-chase. Or toss a fireball at them to clear the way.
Koopa Para Troopa
Watch out for these wily, high-flying turtle aviators. The red ones are more troublesome then the green ones. Winged turtles take two hits—one to clip their wings, and one to send them sailing. They lose their wings when you stomp on them; then they're just like regular Koopa Troopas.
Buzzy Beetle
These "turtles" are encased in a hard shell. A fireball is useless against them. Stomp on it, and it stops moving for a while. You can kick him just like you can kick turtle shells.
The Hammer Brothers
These twin turtles are usually together, and they are the only type of enemy (besides Bowser) equipped with weapons, so watch out! They throw deadly hammers. You'll earn a lot of points by defeating them. Try throwing fireballs or hitting them from below.
Lakitu
Lakitu likes to drop spiny eggs from the clouds—until you stop him. Get him by jumping on him from above. Once on the ground, the eggs that Lakitu drops will hatch and cause even more trouble. When they hatch, they turn into a full-grown Spiny. A fireball is the only thing that can stop the eggs from hatching.
Spiny
Spinies are Lakitu's favorite pets. They are also turtles, but they're extra dangerous because of their thorns. You can't stomp on them; you have to use fire power!
Piranha Plant
These man-eating plants live inside of pipes. They won't come out when Mario is on top of a pipe. You cannot stomp on them, so avoidance is the best strategy. Touch a Piranha's pipe to keep it out of sight. Jump over them with care. You can also kill them with fire power if you have it.
Cheep-Cheep
You'll meet these crafty little fellows in the water and on the bridges. You can't stomp them in the water, so your best bet is to go for them on the bridges. Fireballs will work in either situation.
Blooper
These agile underwater dwellers swim with a squiggly motion. Their favorite activity is chasing Mario; and the only way to stop them from doing so is by hitting them with fireballs. In Super Mario Bros 2 (J), they also appear out of water. You can also walk on the bottom of the water level to dodge bloopers.
Bullet Bill
Mario can duck or jump over these deadly bullets shot from turtle cannons, but he has to be quick. They never stop firing, so keep on your toes! Bullet Bill zips through the land at high speed. Jump on top for points. Fireballs are not effective to bullet bills!!
Podoboo
This lump of lava is a real hot spot. You'll find Podoboos inside of Bowser's castle at the last level of each world. These red-hot deadly stones fly up to strike Mario from bottomless inferno lakes. What's worse, they are indestructible, so avoid them at all costs.
Fire-bars
Small fireballs connected in a chainlike fashion are called fire-bars. Like Podoboos, they are indestructible. But with a little skill (and luck) you can get past them. Stay cool, and watch your timing.
Bowser
At the end of each world, you must face Bowser, the evil King of Koopas. At first, his only tricks are breathing fire and jumping around. Later on, he throws hammers at Mario to slow him down. There are two ways to defeat him:
Get the Axe: Once you get the axe, the bridge automatically topples and Bowser falls into the sea of fire below.
Repeating fireballs: The trick is to shoot Bowser with five fireballs in a row. However, you have to be skillful to dodge his attack while you're trying to blow him away!
If you are desperate, you can sacrifice your power to clear the area. When Super Mario becomes small as a result of enemy attack, he also becomes invincible for a short while. Use these valuable moments to quickly sneak past the unsuspecting Bowser, and get the axe.
Once you defeat Bowser, you're supposed to find the fair Princess awaiting you. But alas, the Princess is held in another castle much farther away, and only her retainers are in the castle to greet you. The adventure continues!