If anyone else is wondering how the characters are generated:

  states = {
    // policeman
    "0": decodeEntities("👮"),
    ...
    // octopus
    "3": decodeEntities("🐙"),

    // explosion
    "4": decodeEntities("💥") 
  };

From http://www.patrick-wied.at/projects/tough-title-city/game.js