Clicking on source is recommended. Unless if you try to play it. Use WASD or arrow keys to move. While moving, the left side is obverse and the right side was inverted. If one of these was next to the wall, both of them may be unable to move. Unless if these pandas move to another direction. There are at least 48 levels total. Sometimes mBlock is a little bit buggy, only 28 levels if you're not on source code. Since the arrow button only works on source code due to code error.