From the Lost Cemetery door, head northeast up the stairs, then go due east from the top of the stairs, and up the next staircase. Continue north east until you reach the unlit brazier; light it, and head through the now-open gate. Head southeast across the bridge and push the lever to drop the ladder, then go back onto the bridge and drop down.
Head south and grab the Large Soul Mass, then head southwest past the tree and drop down, then take the nearby elevator down. Head southeast and walk up the stairs, then use your fire spell to light the fire on the other side of the stairway. This will call a (living) gondola — hop on and ride it across the chasm.
You’ll arrive in the Overgrown Ruins; hop off the gondola and head up the ramp on the other side of the large doorway. Push the lever to open the doorway, then head through it. Continue northeast a little ways and you’ll be able to activate a door back to the Hall of Doors.
Head southeast from the door until you reach a green vine with glowing blue specks — hit it with your sword, and the vine will grab you and place you on the platform above. Break the nearby pots to reveal a Life Seed, then head northwest and jump down the ladder there. Take out the two enemies here, then we’ve got a new mechanic to learn.
See the chubby orange flower? There are two ways to use these plants to destroy the breakable walls that are scattered throughout this area: you can stand near the breakable wall and shoot the plant with a ranged attack, or you can smack it with a melee weapon and then quickly run to the wall. There’s a bit of a delay between when the flower gets hit and when it launches its bomb, so make sure you’re standing near the wall when the plant actually launches its attack. Then roll away so as to not take damage, and voila! You’ve got a new passageway.
Use your newfound knowledge to break the wall that leads back to the door (and note its location in case you die), and also pay attention to where the doorway blocked by vines is — we’ll be returning here in the not-too-distant future. Head northwest past the orange flower, and continue southwest around the big frog statue to find your next bomb-plant. Use it to first open the passageway southeast back to the door, then use it to open the way forward to the northwest. You can easily avoid the two toothy-plants attacks by simply standing near enough that they attack you; you can activate their attack while out of range.
Take out the four enemies in the next area (I like to shoot the orange flower with my bow and let it kill them for me), then grab the key and open the locked gate. Head through, then head to the southwest to grab a Large Soul Mass. Then go back northeast and use the orange flower to open up the nearby breakable wall. Continue northeast through the fireball flowers to grab a Life Seed, then up the stairs to the south and stand near the breakable wall. Use a ranged attack on the orange flower across the path to break the wall, then head through.
Hit the vine to be pulled to the top of the platform, then hit the nearby curled up vines to create a bridge. Continue forward until you reach a ladder. Jump down, then hit the curled-up vine bridge and cross it. Keep going southeast, and go up the next two vine-ladders to reach the Forest Settlement.
Before we chat with anyone here, head due north from where the last vine-ladder dropped you. Drop down at the gap between walls here, then once the camera angle changes, head northwest and get another Magic Crystal shard. Then you can drop down directly south from the shrine, and go the same way you went the first time, up the vine-ladder and then around, and head east into the Settlement.
Once in the Forest Settlement, head north up the wooden platform and climb the ladder. Then head west to grab the Life Seed, and drop down again. Now you can take some time to chat with all the NPCs if you want (it isn’t necessary to proceed, but the dialog can be fun). When you’re ready, drop down the ladder near the NPC with the cat mask, then make your way southwest to a lever. Push it to drop a ladder that leads back to the door, then go kill the three nearby flowers. The vine-ladder will drop, take it up and then jump down to grab the Large Soul Mass.
You’ll encounter some little seed-pod looking enemies nearby. They can only be damaged with ranged attacks, as they’ll hide too quickly if you try to hit them with a melee weapon. You can also deflect their projectile back at them, which will kill them in one hit.
Head southeast, and you’ll soon see a Life Seed over a wall. Head around and grab it, then continue southeast, then northeast to the vine-ladder. Take it up, then drop down to begin another arena fight. There’s a Life-Seed pot in the northeast corner if you need it! Once you defeat the last enemy, the way forward will open in the northwest corner of this area. Head through, then drop down the ladder and continue northwest.
You should see the top of a ladder peeking out at the edge of the nearby ledge — walk close to it, and your camera will swing around. Go up the ladder to grab the Large Soul Mass. Drop down and continue northwest.
Continue northwest down the stairs. Use the orange flower to open up the breakable wall (this is a shortcut back to a previous shortcut back to the door), then head northeast. Head up the western vine-ladder, then go around the corner to the west and use the orange flower to break the wall nearby. Then go down the ladder and push the lever to open a shortcut back to the Forest Settlement.
Head back through the wall you just broke and go northeast, and swing around the northern side of the large circular stone pavilion. Grab the Life Seed back there, then go back around the pavilion and head southeast. Make your way around the corner and continue northwest, and use the orange flower to break the nearby wall. Then use the vine-ladder, and use the orange flower in the next area to break the wall to the east.
Go through and then head southwest to find another wall you can break via orange flower action, and then drop down through the new passageway to grab a Life Seed. Then go back up the way you came, but this time take the ladder up.
Secret: Take one of the vine-ladders just to the northeast, and head north and use the orange flower to break the wall there. Then drop down through the opening you just created and do a plunging attack as you fall. This will take you into a secret-passage — follow it’s end and go into the nearby doorway to find another Vitality Crystal shard. Then exit the room and jump down.
Head northwest until you run into 3 of the orange flowers — this will start an arena fight. Rather than fighting these foes the old-fashioned way, simply run in a circuit, hitting each flower with your sword and then rolling twice to reach the next one. This should eliminate most of the enemies without you having to touch them. Once you defeat the last foe, a ladder will drop — head up it.
Head west then jump down the ladder. Then head due south to another ladder; jump down and push the lever to open a shortcut back to the Forest Settlement. Then go back up the ladder and head northwest to find the Horn.
Grab it, then go southwest past the orange flower and stand by the nearby vine-ladder — don’t take it yet though. Instead, use a ranged attack on the orange flower, then quickly hit the vine-ladder and run to the breakable wall nearby. If you do it quick enough, you should be able to break this wall with the projectile the orange flower launches at you. Head northeast and around the bend to grab the Large Soul Mass, then jump down and head west to the vine-ladder you just took.
This time, jump down the ladder to the south and use the nearby orange flower to break the wall further east. Then return to the Forest Settlement (follow the sign). Talk to the Forest Mother to give her the Horn, and she’ll open the way forward for you. Feel free to chat with the nearby NPCs, then we’re going to head to that vine-covered gate that is now open.
Go south to the ladder just below the Bard (the NPC with the cat-mask), then continue southwest and jump down the long ladder — the entrance to the Mushroom Dungeon is just to the east of the ladder. Head on in when you’re ready!