As mentioned, Bubble Shoot is a very easy to game to learn.
The game rules are very basic, and therefore the game fits all ages as long as you know how to click a mouse, are able to distinguish the colours, and have some sort of logical reasoning that you can apply to the game when you strike the bubbles. The purpose of Bubble Shoot is to remove all the lines of bubbles by aiming and hitting the right ones. Clusters of bubbles are removed when you hit a bubble of a certain colour with your bubble of the same colour. As an integral part of the game, you have to make sure that the cluster of bubbles you decide to aim for is the same colours as the bubble you are aiming and shooting at. You may be lucky that you hit a string or cluster of multiple connected bubbles, but usually you will only be able to remove two, three or four bubbles at a time. If you just hit one bubble of the same colour, the bubbles will not be removed, as you need to hit a string of at least two bubbles (3 including your own bubble).