Course No. 24
Course No. 24 is the secret course of Stove Canyon in Wario Land: Super Mario Land 3, unlocked after finding the hidden exit in Course No. 23. It is a non-linear, maze-like level with many doors and rooms to explore; the goal door can be found early on in the level, although it cannot be opened until Wario has collected enough coins in the level to unlock it first. The central mechanic of the level is ! Blocks that alter the levels of water in some rooms.
Wario begins in a wide room with a Pirate Goom and Dropper on either side. After passing through the door underneath the block containing a Garlic Pot, Wario will enter a large room containing more Pirate Gooms and six doors: three on the bottom floor, and three on the top floor. On the bottom floor, there are small gaps filled with lava Wario can cross over to reach the middle door, which leads to the goal door guarded by a D.D., though beyond that lies a pool of lava that cannot be traversed (unless Wario is Jet Wario). Wario can travel between the top and bottom floors using the ladders. A ! Block that changes the water levels is located next to the bottom-right door of the room.
When Wario enters the room via the top-left door, it is partly flooded. In this state, Wario cannot continue any further from the door unless he is Small Wario or the water is drained, as the start requires Wario to pass through a small gap to proceed. A Penkoon can be found in the middle of the room. After passing through the door on the other side, Wario will find a ! Block, a large block containing a giant coin, and a regular block containing a Jet Pot. Wario cannot return to the main room unless the ! Block is turned on (black).
The middle door on the top floor leads to a tall room with mines and no water at the bottom. Wario cannot reach the ladder to the left unless the bottom is flooded. After hitting the ! Block and climbing the ladder, Wario can reach the upper floor (which was originally flooded) where more mines, another ladder and a block containing a heart can be found. The second ladder leads Wario to a room with a lava pool and constantly rising and sinking platforms that he can use to collect the coins above. Unless Wario is Jet Wario, the ! Block found in this room must be turned off (white) so the second floor of the tall room is flooded, enabling Wario to jump over the wall back to the first ladder to return to the main room.
The top-right door leads to a room that also requires the ! Block to be hit so Wario can use the resulting water to pass over the wall. After doing so, Wario will encounter three D.D.s en route to the door at the end of the room. The door leads to a small room with lava and a floating platform with coins above it. Like the top-middle door, in order to return to the main room, the ! Block here must be turned off so the center of the previous room is flooded and Wario can jump over the same wall as before.
The bottom-right door located to the right of the main room's lava pool leads to a small, dry room with mines on the ground. After turning on the ! Block, the room becomes mostly flooded, enabling Wario to reach the blocks on the right side containing a heart and a key.
After obtaining 10 or more coins, Wario can enter the middle door on the bottom floor of the main room to open the goal door.
The treasure room door is located in the center of the very first room of the level, while the key is in the rightmost block in the bottom-right room. As there is a wide pool of lava on the bottom floor, Wario must carry the key back to the treasure room door by climbing up the ladder on the right side of the room, then down the ladder on the left side towards the bottom-left door where Wario first entered the main room. The treasure is a trophy worth 8,000 coins.