On Celestia.io, you eat to get bigger and try to be the biggest. People you destroy will burst and turn into food.
How to play
Get over the food and grow. You can hurt other players by shooting at them, and if you kill them, they will explode in a beautiful supernova. People will shoot at you, because they see you as food, just like you see them as food. If you need to get away quickly, you can use a boost to move faster but don't use it too often because it throws away mass.
You can move around with your mouse or by pressing the screen. Hold down the left mouse button to fire, and press the space bar or the right mouse button to boost. You can tell how healthy you are by how much glow is around your blob. When you're not being attacked, your health slowly heals itself.
Have fun and good luck!