Your goals will vary from level to level, with different challenges posed by you environment (time of day, blobs locked in ice or captured in bubbles) changing the dynamic of how the linked blobs interact and fall. Plus, there are some mind-boggling challenging levels where you lose blobs to the rising tide, or can dump them into the sea or off a cliff. As you remove blobs, more float in to keep the game going. The number of clicks you get to make matches is determined by your 'mana,' and you can replenish it in-game.
This game is simple on the surface, but its complexities are what will keep you playing and frustrated. That and the cute l'il faces. It's available for free at gamesgames.com.