Evo Planet is described as 'You start as a simple organism, a single cell, and your task is to grow bigger and follow one of the evolution trees. Eat smaller creatures or tasty objects and gain enough mass to evolve into another, more evolved living organism'. There are nine games similar to Evo Planet for a variety of platforms, including Windows, Online / Web-based, iPhone, iPad and Mac. The best alternative is Spore. It's not free, so if you're looking for a free alternative, you could try Diep.io or Mope.io. Other Evo Planet like games are TerraGenesis (Freemium), Agar.io Clone (Free, Open Source), Species: Artificial Life (Free) and Biome3d (Free).
Engage in space exploration and terraform new worlds in this fun and exciting planet building simulator rooted in real science. TerraGenesis dynamically animates entire planets with changing biospheres, all based on real data from NASA.
Real Evolution is a scientifically-accurate natural-selection video game. It allows you to experience evolution first-hand, simulated from the very first principles of evolutionary science: Variation, Mutation, and Natural Selection.