Use the mouse to control the paddle. They are no levels right now. Once you are in, don't make the ball fall off. Once you die, you can press S to open the shop. Right now, you can only purchase extra lives. Others don't work. The very top left is where your score is, below that is the world's best score, and below that is the number of lives you have. To the top right is the level number, and below that is the amount of money the world has (I am working on each person having their own bit of money).
Remember, this is an Alpha version. The collisions are glitchy, and they aren't many features. Comment some features, but I am working on them!