What are the most challenging categories to complete in Little Alchemy 2?

In Little Alchemy 2, some categories are more challenging to complete than others due to the complexity of the combinations or the rarity of the elements involved. Here are the most challenging categories and tips to help you complete them:

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1. Myths and Monsters
- Why it's challenging: This category includes mythical creatures and legendary items, many of which require multiple steps and rare combinations.
- Key elements: Dragon, Unicorn, Phoenix, Kraken, etc.
- Tips:
- Start with Life and Fire to create Phoenix.
- Combine Lizard and Fire to make Dragon.
- Use Horse and Rainbow to create Unicorn.
- For Kraken, combine Ocean and Monster.

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2. Space
- Why it's challenging: Space-related elements often require combining abstract concepts or multiple layers of combinations.
- Key elements: Black Hole, Galaxy, Solar System, etc.
- Tips:
- Combine Star and Star to create Galaxy.
- Use Galaxy and Galaxy to make Universe.
- For Black Hole, combine Star and Pressure.
- Create Solar System by combining Sun and Planet.

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3. Science
- Why it's challenging: This category involves advanced concepts and often requires combining elements from other categories.
- Key elements: Atom, Molecule, Bacteria, etc.
- Tips:
- Combine Air and Air to create Pressure, which is essential for many science-related elements.
- Use Energy and Primordial Soup to make Life, which leads to Bacteria.
- For Atom, combine Energy and Stone.

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4. Big
- Why it's challenging: This category includes large-scale elements, many of which are hidden or require specific combinations.
- Key elements: Continent, Mountain Range, Solar System, etc.
- Tips:
- Combine Earth and Earth to create Land.
- Use Land and Land to make Continent.
- For Mountain Range, combine Mountain and Mountain.

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5. Rare and Hidden Elements
- Why it's challenging: Some elements are not obvious and require specific or non-intuitive combinations.
- Key elements: Time, Immortality, Philosopher's Stone, etc.
- Tips:
- Combine Life and Time to create Immortality.
- Use Stone and Philosopher to make Philosopher's Stone.
- For Time, combine Sand and Glass to create Hourglass, then combine Hourglass with Life.

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General Tips for Completing Categories:
1. Use the Encyclopedia: Check your progress and missing elements in the in-game encyclopedia.
2. Experiment with Combinations: Try combining elements from different categories to discover hidden items.
3. Focus on Base Elements: Many advanced elements are built from basic ones like Earth, Fire, Water, and Air.
4. Look for Patterns: Some elements follow logical patterns (e.g., combining two of the same element often creates a larger version).

By focusing on these categories and using the tips above, you can systematically work toward completing the most challenging parts of Little Alchemy 2. Good luck!