It's OK
The game's point is to move the mouse around the screen and "touch" the cannon balls as they come in. It would seem pretty easy but the three ships firing on you seem to have countless cannons and the game starts with more than a dozen cannon balls comming your way.
Making things all the more difficult is that the cannon balls are black, the attacking ships are black and your ship is also black. Your point of view is through black netting and all of your rigging so it's really hard to see the cannon balls.
Maybe this game is just not for me, but I see no point. There is no way to return fire on the enemy and there are no "power-ups" to slow things down or improve visibility or increase the area effected by your pointer.