The debate surrounding the role of the compact city in the twenty-first century is often characterised by questions on the roles of high-density, mixed use transport efficiency (Dempsey, 2010; Verheij et al., 2024), and social and economic diversity. While these concepts are discussed holistically throughout, this research reflects in particular on the theoretical and empirical characteristics of multiple levels of mixed usage within compact cities for a series of building typologies. This text therefore only presents some of the complex arguments, design guidance, and implications for policy behind the compact city concepts, as well as densification changes not only for the environmental performance of building typology and morphology but also its social dynamics (Burton, 2000; Dempsey et al., 2012). The findings are not conclusive nor wholly inclusive as a fit-for-all for any particular urban form. Extending this discussion of the compact city to various forms of hybridity as well as to hyper-morphology, the final section outlines where the scope lies for further research.