Fireboy and Watergirl 4: Crystal Temple is a two-player cooperative puzzle game that challenges players to control two characters with distinct elemental abilities. Together, they must overcome obstacles and escape the mysterious Crystal Temple.

1. Collect Diamonds: Gather all diamonds corresponding to each character in the level (red for Fireboy, blue for Watergirl) to achieve the highest score. Occasionally, gray universal diamonds appear in levels, which either character can collect.
2. Overcome Hazards: Utilize each character's elemental immunity (Fireboy is immune to lava, Watergirl is immune to water) to avoid their respective deadly obstacles and the shared green venom.
3. Solve Puzzles: Cooperatively operate various mechanisms—such as levers, buttons, crates, and portals—to clear obstacles from each other's paths.
4. Reach the Exit: FireBoy must enter the red exit door, while Watergirl must enter the blue exit door.

Two-Person Operation and Collaboration

The game requires two players to work closely together. One player controls Fireboy, while the other controls Watergirl. Most level puzzles demand both characters to cooperate to solve them.

Elemental Immunity and Weaknesses

• Fireboy: Immune to red lava damage, but contact with blue water will cause instant death.
• Watergirl: Immune to damage from blue water areas, but contact with red lava will result in instant death.
• Common Weakness: Both characters will die instantly upon contact with green venom.

Clearance Requirements

To clear the checkpoint, all of the following conditions must be met simultaneously:

• Fireboy reaches the red exit door
• Watergirl reaches the blue exit door Both characters must reach their respective colored exits simultaneously.

Collection Targets

• Collecting diamonds of matching colors grants bonus points
• Diamond collection is optional (except in specially marked levels)
• Collecting all diamonds achieves a perfect completion rating

Is this game for one player or two players?

This game is primarily designed for two-player co-op. While an experienced player can attempt to control both characters simultaneously in single-player mode, it is extremely challenging. The core of the game's enjoyment and design lies in the communication and collaboration between two players.

What are portals? How do I use them?

Portals are a new mechanic introduced in the Crystal Temple generation. White portals connect to other white portals, while black portals connect to other black portals.

Do I have to collect all the diamonds to clear the level?

It is not mandatory. The only requirement to clear the level is for both characters to reach their respective exit doors. However, collecting all diamonds allows you to achieve a higher score (S-rank), which is important for players pursuing perfection or unlocking hidden content.

Can the Fireboy and the Watergirl touch each other?

Sure. The two characters can touch each other, stand together, and even stand on top of each other. Their only restriction is that they cannot touch each other's elemental liquids (water is deadly to Fireboy, lava is deadly to Watergirl), and neither character can touch the green poison.