We aim to improve on the design of procedurally generated game levels. We propose a method which empowers game designers to author and control level generators, by expressing gameplay-related design constraints. Following a survey conducted on recent procedural level generation methods, we argue that gameplay-based control is currently the most natural control mechanism available for generative methods. Our method uses graph grammars, the result of the designer-expressed constraints, to generate sequences of desired player actions. These action graphs are used as the basis for the spatial structure and content of game levels; they guide the layout process and indicate the required content related to such actions. We showcase our approach with a case study on a 3D dungeon crawler game. Results allow us to conclude that our control mechanisms are both expressive and powerful, effectively supporting designers to procedurally generate game levels.