To start evolving creatures, open evolve.html or http://acruikshank.github.io/deathmatch/evolve.html in a modern browser and hit the 'skip' button. You may toggle in and out of accelerated mode by clicking the space bar. In accelerated mode, it should take a minute or two (in the beginning) to complete a generation. After 3 or 4 generations, you should see creatures that have evolved to fall slowly. After around 8 generations you should see some creatures that can move and somewhere between generation 10 and 20 you'll get creatures that are evolving on their fighing skills. The ecosystem will usually peak between 80 and 120 generations and after that you'll mostly see stasis and even regression that will later be punctuated by wild and sudden swings in population dynamics.
If you'd like to be able to save your progress, install standard configurations of MongoDB and Node.js, and then run 'npm install' and 'node server.js' from the project root. Go to 'http://localhost:9024/evolve.html' and this time enter a simulation name before clicking begin. Later, you may type the same simulation name to continue the evolution simulation where you left off. You may also go to 'http://localhost:9024/replay.html' and enter the same simulation name and a generation number to replay any of the matches in a single generation.