This thesis looks at videogames as spatial constructs. Aarseth declares, videogames are "essentially spatial in nature" and it is this spatiality that separates them from other media. Investigating the spatial aspects of videogames becomes essential to understanding them. Using architecture as a tool to unpack spatial conditions this thesis looks at video game environments as architectonic, as artificial constructs and as architecture, arguing that all environments in a videogame are architectural, even landscape. Architecture is something built, the art and science of building. However this thesis holds as central the notion that architecture is more than just buildings. Architecture is about structure, organisation and identity. Within videogames architecture becomes a means of organising, managing and structuring the game world. This thesis analyses game space in conjunction with gameplay and player agency, looking at spatial production as experiential or symbolic, exploring environments for ludus and paida, defining common patterns of spatial use and studying architectural function. But while many videogames are virtual worlds, not all virtual worlds are games. This thesis then also looks at non-gamic virtual worlds as spatial constructs, taking what is learned from studying videogame environments and looking for similarities and differences between the two similar phenomenons.