To get to that secret dungeon, you need to go through many palace halls. And, of course, none of them can be without protection. Among the many bubble warriors, hidden keys that open the doors to the next room. Shoot them down by shooting bubbles of the same color and destroy structures. For especially persistent warriors, powerful projectiles will be given to you. Use them as needed and try not to pile up structures so as not to get into dead ends. Pass all the tests, get to the main hall and find out what is hidden behind its gates.