Simple yet challenging casual game
This is a great idea for a game but it feels a bit like a work in progress, because there's a major problem that you should fix ASAP: swimmers can be eaten by sharks when they are still off screen at the top or bottom, so I was losing points for not saving swimmers that I couldn't even see, let alone click and drag.
Also, you might want to consider having the "saved" swimmers on the sides swim away off screen instead of just floating around, because I only skimmed the instructions the first time and in the chaos of the game, I didn't really notice that I had saved the swimmers that I'd dragged to the sides. I might've figured it out while playing if the sharks and swimmers didn't overlap the dashed lines so much. I understand that you probably want the player to accidentally drag the sharks into the "safe" areas, but it just doesn't seem to make much sense that the swimmers would stick around. If you really want the player to drag the sharks, then maybe you should have one side be for the sharks and the other side for the swimmers.
Again, great idea and the art / animation is really fun, especially how the swimmers hold onto the mouse cursor, and how the body parts are randomly dispersed when the swimmers get eaten.