Super Mario World/Iggy's Castle

The first screen is a series of long fences. This place is great for getting lives. Grab the fence, and hit each of the koopas holding onto the fence from above. There are enough koopa's to get 4 or 5 lives in this screen alone. The second screen automatically scrolls, with giant pillars dropping down trying to squish you. Avoid all the pillars by staying either at the far left of the screen, or the far right. Careful of the last pillar since there is a gap below it with moving blocks. If you are Super Mario, on the way you will be able to get a Fire Flower from a flying block. If you are small it will only be a mushroom. Once you reach the big red door, enter to fight Iggy Koopa. Inside, there is a half platform floating on a pool of lava, tilting left and right. To defeat Iggy, you must push him off the edge into the lava. Either jump on him, or shoot him with fireballs and he will slide down the platform.