Only two more Worlds remain in your adventure. World 6-1 looks a lot like the World of Deserts in World 2, but you'll run into more enemies and quicksand here. You'll have to look hard to find the key in map B.
Careful on the quicksand. If you pause when crossing the quicksand, you might start to sink. You can jump repeatedly to pull yourself out of the quicksand. If you don't respond quickly, you'll lose a life.
(1) Sub-space 1. First defeat Cobrat, then go inside the jar. As soon as you pull out the clump of grass and find the Potion, make a door to Sub-space on the bone to the right. The second that the Mushroom appears on the quicksand, grab it before it sinks beneath the surface!
(2) Shells in jars. You will see two jars sitting side by side. But after you defeat Cobrat and go in, all you'll find is a Turtle Shell, which isn't too effective a weapon on this stage…
(3) Sub-space 2. Take the potion to the top of the hill between the two cactus plants and you'll get a mushroom in Sub-space. But don't get careless—Pokey and Panser will try to stop you. And they mean double trouble.
Pokey to the rescue: in, the A-coins are stashed pretty high up in the air. Even Luigi will have trouble collecting them unassisted. There's no need to strain yourself. Just hop on top of Pokey for an added boost. And when you're done, take out the bottom segment for a huge amount of points.
(4) Where's the Key? Twenty-one jars?! Where's the key to the door? Try the fifth jar from the right. Take care to avoid the Shyguys that infest the vase until you have the Key. Then you can toss the Key at your enemies. A 1-Up is hidden in the third jar from the left.
Two patches of grass have been added above the door that leads to the mini-boss. Jump up to them, pull them up, and you'll discover a potion. Carry the potion back to the left and drop it in order to create a door in the middle of the jars. Step inside, and you'll find that useful third hidden mushroom.
(5) Fire-breathing Birdo! Birdo shows up again, but in this world she can only blow fire. And she's not so hot at that. Destroy her with three hits from the Mushroom Blocks to the left.
After defeating Birdo, grab the Crystal Ball and head through the hawkmouth gate.