The basic idea of Perlin noise is to add layers (octaves) of noises. Higher octaves are more precise, in that they have more points (higher frequency), but are (usually) less weighted.
Ken Perlin designed Simplex noise as a more scalable replacement to Perlin Noise - but the two algorithms are often both referred to as Perlin Noise.
Two competing methodologies in procedural content generation are teleological and ontogenetic. The teleological approach creates an accurate physical model of the environment and the process that creates the thing generated, and then simply runs the simulation, and the results should emerge as they do in nature. The ontogenetic approach observes the end results of this process and then attempts to directly reproduce those results by ad hoc algorithms. Ontogenetic approaches are more commonly used in real-time applications such as games. (See "Shattering Reality," Game Developer, August 2006.)
Se puede usar una función de fitness sobre diferentes mapas para ordenarlos según dificultad. Se puede aproximar una cantidad de posibles soluciones al mapa, y tomarlo como vector de dificultad. Cuantas más maneras de ganar, más fácil es el mapa.