Course No.31 is the first course of Parsley Woods in Wario Land: Super Mario Land 3. The level takes place over the lake. After clearing Course No.32 and draining the lake, however, the level's layout changes when Wario revisits it, similar to Course No.01 and Course No.03 in Rice Beach after the high tide. Because of this, the level can no longer be played in its previous state following the drainage.
Most of the level involves Wario swimming across stretches of the lake's water, with many abysses at the bottom that instantly cause Wario to lose a life if he sinks too deep. The first block Wario finds upon diving into the water contains a Garlic Pot. Throughout the level, Spiked Balls drop from the trees onto the platforms below, roll towards Wario and sink into the water or hit a wall and fall off-screen. A few Yarikuri Obake also appear in the level.
In the first part of the level, coins can be found under the platforms on which the Spiked Balls drop. Later on, Wario must climb a set of stairs while avoiding the Spiked Balls that roll down them. A room holding the checkpoint can be found halfway through. Following the midway point, many more Spiked Balls fall from above, landing on the large blocks floating above the water, then proceeding to sink into the water and continue rolling along the lake floor before falling into the abyss and disappearing entirely. Rows of coins are found under the blocks. After jumping over a wall, two more Spiked Balls drop onto blocks containing hearts and coins and into the lake. After reaching land and avoiding another Spiked Ball, Wario will find the goal door.
After draining the water in Course No.32, the bottom of the lake becomes accessible. Spiked Balls and Yarikuri Obake no longer appear in the level, while many Guragura roam the level's lower portion. Upon dropping down or using the ladder to reach the bottom, Wario must break through multiple breakable blocks to proceed further. After climbing over a small set of stairs and up a ladder, Wario will reach the larger set of stairs over the lake's surface from his first visit, where a Guragura awaits at the top. Underneath the stairs at the lake's bottom are two Piranha Plant beds, with a small part of ground in between them, as well as a block containing a Star. A ladder on the right takes Wario back to higher ground should he fall in. After crossing over the hill, a Guragura wanders back and forth underneath two platforms surrounded by coins and two blocks next to them containing a Garlic Pot and a heart, just before the ladder leading up to the checkpoint door.
Following the halfway point, Wario will find several ladders that lead up to the large blocks where the Spiked Balls originally landed and the coins underneath them can still be found. At the bottom, many more coins can be collected, though the path is blocked by several breakable blocks. After Wario passes under a low ceiling and encounters more Guragura, a small bottomless pit lies just before the ladder leading up to the surface where the goal door is found.
The key is located near the start of the level among the breakable blocks, while the treasure room door is located at the end under the last ladder in the level. Wario must carry the key all the way to the end of the level while avoiding the enemies and the bottomless pit towards the end. To access the door, Wario can ground pound the single breakable block underneath the final ladder as Bull Wario, or drop down the narrow chasm just before the goal door. The treasure is an artifact resembling Wario's head worth 8,000 coins.
Enemies and obstacles