In Eufloria, the player controls trees that grow in the outer space. It was inspired by a scientific theory put forward by the famous astronomer Freeman Dyson and was initially called Dyson in his honor.
The player oversees the breeding of a plant, called Dyson tree, that can grow on comets and asteroids in the vacuum of space. The tree produces seedling that can be used to spread the species to many planetoids. According to the game's backstory, the trees try to make the planets habitable for an ancient extraterrestrial race called Growers who created the trees. They have to fight against a rival species, the greys, who are the evil, mutated version of Dyson trees.
The game is divided into levels. At the beginning of each level, the trees already inhabit an asteroid. The goal is to spread the trees to other asteroids. The seedlings are the units the player directly controls. They can be used to defend the trees from the enemy seedlings. They can explore the space to find new planetoids. It takes ten seedlings to start growing a tree on a planetoid. Larger asteroids take more time to grow a tree on. However, they eventually reward the player with better seedlings that move faster and have a wider range.
Eufloria is very minimalist in its visuals. All of its elements are composed of simple geometric shapes. The game is set to equally minimalistic ambient music.