Cave Story/Plantation

Upon exiting the room with Itoh you will find yourself in the plantation. This map is quite large and there is a lot to do here.

Unidentified Path
Immediately above you there is a path going up through the rock which you can go up through a series of jumps or fly, it leads to an unidentified path which leads to a room full of statues and what looks like a treent sipping a margarita.

Curley
Immediately down you will find a similar jump path boring down into the side of the mountain. If you saved Curley and successfully drained her of water, you will find her bedridden at the bottom room, next to a creature who found her. Speak to the creature, then to curley, then to the creature again to find out that Curley has lost all her memory and that the cure is to eat a special mushroom. If you want the best ending you must find and feed her this mushroom (before leaving the plantation to the next step?)

To save several tedious trips through the outer wall and now destroyed egg corridor, you should probably first find one of the two teleporters in the plantation before proceeding to procure a cure for Curley.

Go back to the now abandoned mimiga village, enter the graveyard, at the top left there is a door that was previously unreachable, fly up there and you will find a mushroom called Ma Pignon. Talk to him about Amnesia and he will ask if you are sure you want the mushroom badge, you will have to say yes every time he asks if you want it, and say no every time he asks if you don't want it, eventually you will get the mushroom badge. Do NOT leave yet. You must now go into the inventory and examine the mushroom badge, this will reveal it to be a useless trinket. Go back to Ma Pignon, he will laugh at you for buying into the whole badge thing. After a short dialogue he will ask if you really want to eat him, I am not sure what saying no does, but saying yes initiates combat. He is a pushover boss, after defeating him you get him in your inventory and can feed him to Curley to cure her amnesia. Go back to Curley, shove Ma Pignon in her mouth, and watch as she regains all memory, even memories from before you met her. You get the Iron Badge item.

Prison #2
Far to the left you will find a prison full of Mimigas, you can talk to them to gain valuable hints and clues. But if you are following the walkthrough that is not really necessary. There is a secret tunnel at the left top part of the prison that is laughably easy to find, it leads to a teleporter which leads to the grasslands, the teleporter in the grasslands is now active and can be used to teleport back to the plantation.

Rest Area
Here you will find the fisherman, spare sprinklers, and resting mimigas. Talk to the fisherman to get him to go fishing. Most Mimigas will not talk to a Human.

Teleporter Room
At the bottom part of the level there is a long stretch of water, finally leading to a teleporter room that allows direct teleportation to the Mimiga village (and back), it requires a key which is stuck in an instant death trap, don't try to retrieve it yourself. Find the mimiga's break room, talk to the fisherman, he will go fishing and fish out the key for you.

When you try teleporting for the first you will be knocked out and put in prison, this will advance the plot.

Prison
Talk to the mimiga imprisoned with you twice. Check your inventory, read the letter from sue. This will open up the tunnel in the back of the prison allowing you to escape, and provide you with the password for the Hideouts, where Sue's mother is working against the professor. It is found to the right of the Rest Area, through some easy to navigate and short tunnel.

Hideout
You will temporary lose your jetpack 2.0 after talking to Sue's mother. Don't worry, while it sounds like the loss is permanent, you get it back in short order. Sue's mother gives you a mimiga mask and asks for a sprinkler. Go all the way left and find a broken sprinkler, take it back to rest area, talk to the guy watching over the new sprinklers, and he will swap with you. Take the new sprinkler to Sue's mother.

She now needs Itoh's help, go all the way to the right to where you entered the plantation originally, find Itoh, he will give you a remote for Sue's mother. She will use it to finish the rocket which will allow you to progress to the next level. Sleep, then talk to her to get back your jetpack. You don't have to fly up yet, and if you use the jetpack 2.0 to fly down you can get back down through the deathtrap safely and easily.

Health Boost
At the top right end of the level you will find a health capsule which gives +4HP.

Puppy
There might be a puppy near the top of the level, where you have the 4 red skull warning signs (and where you must pass to get to the next part). The puppy is grateful for your help before and gives you a +5HP health capsule.