What Wazzup said, 'cept he got the order wrong, I think.
- Desert: [Optional, but heavily recommended] Refuse the machine gun Curly offers. Keep your Pole Star.
- Labyrinth (1): [Optional, but heavily recommended] Refuse the trade with the cockroach guy. Keep your Pole Star.
- Labyrinth (2): Skip the Booster. When you see Professor Booster fall down, don't go see him and jump past the chasm. You should barely make it.
- Core Room: Once you activated all the door and Curly moves to the actual boss room, don't talk to her right away. Examine the floor in the far right corner - you should find a tow rope. Once you beat the boss, interact with Curly and you'll have the option of taking her with you with the Tow Rope.
- Waterway: Go to the cabin and once you're there, do what Wazzup said.
- Mimiga Village: Before going to the Egg Corridor?, Prof Booster should come in and give you the Booster 2.0. Also, if you still have your Pole Star, use the Booster to go to the very top of Mimiga Village, back into the first cave in the game. Talk to the guy at the end of that cave and he'll give you the Spur. Take it.
- Outer Wall: Timer item is not mandatory, but might as well get it.
- Plantation: Do what Wazzup said.
- Return to Mimiga Village and do what Wazzup said. The Ma Pignon will be a bit annoying, since you'll have to answer a few questions before he even gives you the fake item (which you should then examine, and talk to him again).
- Plantation: Go speak with Curly until she gives you the Iron Bond.
- Last Cave (Hidden): If you did everything correctly, the Last gave will be much harder. Good luck!
- Prefab House: After the final battle with the Undead Core, as you're escaping, you should be able to get into the small house. Whatever you do, do NOT save unless you have full health. Do not. Redo the final fights if you lost some HP on the way to the Prefab House. Trust me on that. Anyway, once you're there with full health, save, and then jump in the hole on the left.
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When you have nothing to say, quote yourself ~ Solfadore