Even though they try to get out, Fireboy and Watergirl are still stuck in strange temples. They have to figure out how to solve the problem and get out by working together. When you're playing by yourself, you can move each character individually or try to move them all at the same time. But the game is much more fun when you dress up as different characters and play with friends or siblings.
You should know that Fireboy is immune to fire, so he can walk freely in the bubbling lava pools, but be careful when you get into the water. Boys and girls have to run and jump between fire and water at each temple. The water girl can live in puddles, but she gets hurt when she goes into the lava. Sharp things on the road should be watched for by both. The goal of each level is to get to the temple doors that lead to the next room. Bring a blue sign to the door if you're in the Water parity, and a red sign if you're in the Fire parity. As they travel, both characters should look for their own color of the gem. As you get closer to the door at the end of each level, your score and rank will go up faster.
You have to push the buttons that turn on the elevator, the push box, and the brick that will help you get higher. You also have to change the switches to find the solution for each level.
But the game isn't just about running and jumping over pits of death. You'll have to work as a team, with one character holding down switches or platforms so the other can pass. In the end, you'll have to find a way to get the two characters back together. Some stages just want you to get through them as fast as you can. Everyone will tell you to move both heroes at the same time. Some people still won't let you leave until you bring them special things. You'll get a score at the end of each section based on how well you did. If you want to get a higher score or get better at using water and fire, you can go back and play the earlier levels again.