Fireboy and Watergirl 4: Crystal Temple Game

Fireboy and Watergirl 4: Crystal Temple is the fourth entry in Oslo Albet's cooperative puzzle-platformer series, and it's built around two characters with opposite weaknesses. Fireboy walks through lava without a scratch but dies the instant he touches water; Watergirl swims through water fine but dies in fire or lava. Green ooze kills either of them on contact, so both of you have to route around it. The goal in every level is simple to say and often hard to do: get both characters to their own matching door at the same time.

What sets Crystal Temple apart from the earlier temples is its portal system. Rooms contain portals lit either white or black, and walking into one teleports that character to one of two possible exit points tied to that portal's color. Picking the wrong portal, or sending a character through at the wrong moment, can strand you on the wrong side of a puzzle, so timing who steps into which portal — and when — becomes as important as the platforming itself.

Controls

• Fireboy: Arrow keys to move and jump.
• Watergirl: W, A and D to move and jump.
• R restarts the current level.
• Play solo by running both control schemes with two hands, or split them across two people on the same keyboard.

Tips

• Scout a portal room before sending anyone through it — stepping in blind is how you strand a character on the wrong side of a switch.
• Use one character to hold down a lever or pressure plate while the crosses the gap or platform it opens.
• If you're playing solo, clear the immediate obstacle for one character before switching your attention to the rather than trying to track both at once.

It's built for two people sharing a keyboard as much as it is for solo players who like coordinating two characters at once — either way, it rewards patience over speed.