Mope.io

A survival arena organised as a food chain. You start as something very small, eat berries and water to grow, and evolve through a long ladder of animals — each of which can eat the tiers below it and be eaten by the tiers above. The entire game is knowing where you currently sit on that ladder. What makes it work is that the hierarchy is strict and visible. There is no fighting an animal two tiers above you, so the answer is always to leave, and the tension comes from needing to be in the water or near a particular food source that something larger is also using. Each animal has a special ability and a habitat where it is strongest, which gives the evolution real texture — a tier that is helpless in open ground can be dominant in water. Progress is lost on death, which is the cost that makes the caution meaningful. Sessions are open-ended, the map is large enough to hide in, and the early tiers go quickly so a bad death is annoying rather than ruinous. It plays fine on a phone and the ability timings reward knowing your current animal rather than reacting faster.