This paper investigates strategies to generate levels
for action-adventure games. For this genre, level design is more
critical than for rule-driven genres such as simulation or rogue-like
role-playing games, for which procedural level generation has been
successful in the past. The approach outlined by this article distinguishes
between missions and spaces as two separate structures
that need to be generated in two individual steps. It discusses the
merits of different types of generative grammars for each individual
step in the process. Notably, the approach acknowledges
that the online generation of levels needs to be tailored strictly to
the actual experience of a player. Therefore, the approach incorporates
techniques to establish and exploit player models in actual
play.