Apescape

You spawn as a gorilla which can run left or right, and jump. The giant wall of monkeys is to your left, and proceeds towards you. You must thus run away from it, avoiding vertical tree logs, pits and spikes. The wall of monkeys is slower than your running speed. Death is caused by being engulfed with this wall of monkeys (there is a small comfort zone even inside the wall), or falling into spikes.