How to clear Attic Stage, also known as Final Boss: One Mighty Mouse! in Super Mario Land 2: 6 Golden Coins.
How to Clear Attic Stage
Go to the right and hit the ? Block, but watch out for the Goomba that walks toward you. The ? Block contains a Super Mushroom or Fire Flower. To the right, there is a Koopa Troopa.
After that, there is a ? Block that contains a 1-Up Heart, but a Collector steals it. Chase after the Collector and touch the 1-Up Heart to take it back. Then get the coins between the books.
After that, there are two Goombas, and then there is a Piranha Plant in a pipe on a shelf, and below that there is a conveyor belt with coins above it, but there are spikes at the end of the conveyor belt, so you might want to run to the left to avoid the spikes, or you can just try to jump up onto the ledge without hitting the spikes.
Jump past the spikes and go to the right, where there is a Piranha Plant coming down from a pipe. Then there is a Koopa Troopa, and a ? Block that contains a Carrot.
Before you continue, jump onto the Block that had the carrot in it, then jump onto the ledge on the left. Keep jumping up the books, and you will hit a Hidden Block that contains a Moneybag. There are also coins above the Moneybag.
After that, don't try to hover to the right, because there are spikes to the right that will stop you. Instead, go back down below, then go to the right and jump up the books. There is a Goomba on top. Beneath the table, there are two Goombas.
After that, there is another ? Block with a 1-Up Heart, but a Collector will try to steal it. Try to stand where the 1-Up Heart will land, and you will take it from the Collector right away.
Go to the right, but don't try to hover right, because there are more spikes on the right that will stop your progress. A pipe near those spikes contains a Venus Fire Trap.
Go to the right and hit the Midway Bell. There is a pipe after the bell that has a Piranha Plant.
Go to the right, and there are two Goombas coming down the books. You might want to wait to hit the ? Block, because it gives you a Super Mushroom or Fire Flower, but if you're Bunny Mario, it's easier to get the coins below. There is a Paragoomba after the ? Block. After you get the coins, if you didn't hit the ? Block to get a Fire Flower, do so now. Then go to the right, past Paragoombas and walls of spikes (don't let the conveyor belt push you into them), and go through the pipe.
Sewer Rat
The Sewer Rat will run out of a random pipe and run across the floor, then will climb up the wall and enter a pipe there, or will climb up to the ceiling and fall down from the center, so make sure not to stand beneath it.
Stomp the rat whenever it's not on the wall or about to jump onto the wall. Keep using this strategy until the rat is defeated.
After the Battle
After you defeat the Sewer Rat, the Macro Coin appears and goes into the gate at Wario's Castle. An "X" flag appears above Macro Zone (but you can still redo the levels there if you wish).
If you got all six golden coins, you can now proceed to Wario's Castle in the middle of the map. The entrance accessible from the southern part of the map, near Tree Zone.
Now you can go to any of the other zones:
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