In this game, you're a fish, and you, um, extrude a chain which follows you as you move around. You can cross over the straight segments of your trail, but not the corner pieces.
Your mission is to link together the various blocks which spawn around the grid. Move through the boxes either vertically or horizontally, depending on the lines they have on them.
Each block has a number on it, and when you link a block together with another block, it will start sending its contents to the next block in the chain, and its number will count down. When the number reaches zero, the block will disappear and you will earn one point.
...it makes more sense when you play it?
It is very hard to get 100 points. If you can get to 100 points, you may enter the Cool Kids' Club.