Draw a rectangular shape around the bugs by your mouse and if it looks like a rectangle then you will catch all bugs which are inside it. Otherwise the shape will be disappeared.
You can't draw a new shape over the existing rectangles.
If any bug touches your current shape while you are drawing it then the shape will be destroyed and your pen power will be decreased proportionally to the size of that bug. The game is over when the pen power is 0%.
Game Controls
Use your mouse to draw rectangle shapes.
To go to the next level you have to catch all bugs but you are also limited with the maximal size of the canvas space that can be filled with your rectangle drawings.
The current color of your pen has the sense only if you want to get more points. In that case you have to catch those bugs with the same color as your pen. Otherwise you can catch any bug with any pen.