In celestia.io, you control a circular celestial life-form in a race to become the largest of them all. Stars are your food – the more you eat, the bigger you'll become. To aid your quest, you may use boost, which makes you faster, or fire red stars at hostile life in this universe.
But beware of red stars flung in your direction by other beings in this universe. If those red stars collide into you, you'll lose some of your life force – the glow around you which keeps you alive. If you run out of life force, you will explode in a spectacular supernova, returning your mass to the universe for others to feed on.