Push the bubble with your fingers, find a ball hidden behind (hidden ball), tap it, explode and destroy bubbles and enemy characters.
It is clear if you defeat the boss character that comes out at the end.
When you tap a yellow hidden ball, a part of the wall will disappear, so lets hurry and drive out bubbles and enemy characters.
Lets put a bubble close to the hidden ball once you catch it with your finger.
As the concealed ball sticks around, let s take it close to the enemy character as it is and let it explode.
"List of Effects of Hidden Balls"
(Blue) A normal explosion. Extensive explosion occurs.
(Green) Explode in a few seconds after tapping. The blast range is the same as "blue".
(Red) The bombardment range is narrow, but if the bubbles are in close contact with each other, it triggers a chain explosion of the bubble.
(Yellow) Although it does not explode, part of the wall disappears. Bubbles and enemy characters can be driven out.
(Skull) bubble occurs.
You can use the thunder (button at the bottom right of the screen) to destroy all the continue and bubbles after the game over once.
Also listen to the sounds when the bubble can be played and have fun.