The makers of Super Mario Bros. were pretty into recycling — not only are the clouds and bushes the same sprite, but the big castle that proceeds Bowser levels is just cobbled together from multiple small castles.
Super Mario Bros was only supposed to be the only Mario game in the series but since they got good success in the game they made more now there is 171 Mario games and Nintendo is still making more.
Players are given a certain number of lives, and may gain additional lives by picking up green and orange 1-Up mushrooms, collecting 100 coins, defeating several enemies in a row with a Koopa shell, or bouncing on enemies successively without touching the ground.
A red and yellow Super Mushroom, Mario grows to double his size and can take one extra hit from most enemies and obstacles, in addition to being able to break bricks above him.
Another is the Fire Flower; when picked up, this item changes the color of Super Mario's outfit and allows him to throw fireballs, or only upgrades Mario to Super Mario if he has not already.
Mario's primary attack is jumping on top of enemies, though many enemies have differing responses to this. For example, a Goomba will flatten and be defeated, while a Koopa Troopra will temporarily retract into its shell, allowing Mario to use it as a projectile. These shells may be deflected off a wall to destroy other enemies, though they can also bounce back against Mario, which will hurt or kill him. Another attack, for enemies standing overhead, is to jump up and hit beneath the brick that the enemy is standing on.